diff --git a/desktop/sources/scripts/cursor.js b/desktop/sources/scripts/cursor.js
index 57759c1..47d1b4f 100644
--- a/desktop/sources/scripts/cursor.js
+++ b/desktop/sources/scripts/cursor.js
@@ -99,7 +99,7 @@ function Cursor()
 
   this.pos_snap = function(pos)
   { 
-    var grid = dotgrid.tool.settings.size.width/dotgrid.grid_x;
+    let grid = dotgrid.tool.settings.size.width/dotgrid.grid_x;
     return {
       x:clamp(step(pos.x,grid),grid,dotgrid.tool.settings.size.width),
       y:clamp(step(pos.y,grid),grid,dotgrid.tool.settings.size.height+grid)
diff --git a/desktop/sources/scripts/dotgrid.js b/desktop/sources/scripts/dotgrid.js
index f56278d..a901fe6 100644
--- a/desktop/sources/scripts/dotgrid.js
+++ b/desktop/sources/scripts/dotgrid.js
@@ -48,7 +48,9 @@ function Dotgrid(width,height,grid_x,grid_y,block_x,block_y)
 
   this.open = function()
   {
-    var paths = dialog.showOpenDialog({properties: ['openFile'],filters:[{name:"Dotgrid Image",extensions:["dot","grid"]}]});
+    if(!dialog){ return; }
+
+    let paths = dialog.showOpenDialog({properties: ['openFile'],filters:[{name:"Dotgrid Image",extensions:["dot","grid"]}]});
 
     if(!paths){ console.log("Nothing to load"); return; }
 
@@ -76,7 +78,7 @@ function Dotgrid(width,height,grid_x,grid_y,block_x,block_y)
   this.save_web = function(content)
   {
     console.info("Web Save");
-    var win = window.open("", "Save", `toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=640,height=480,top=${screen.height-200},left=${screen.width-640}`);
+    let win = window.open("", "Save", `toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=640,height=480,top=${screen.height-200},left=${screen.width-640}`);
     win.document.body.innerHTML = `<style>body { background:${dotgrid.theme.active.background}; color:${dotgrid.theme.active.f_med}} pre { color:${dotgrid.theme.active.f_high} }</style><p>To save: Copy this into a .grid file.<br />To load: Drag the .grid onto the browser window.</p><pre>${content}</pre>`;
   }
 
@@ -118,7 +120,7 @@ function Dotgrid(width,height,grid_x,grid_y,block_x,block_y)
   this.export_web = function(content)
   {
     console.info("Web Export");
-    var win = window.open("", "Save", `toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=640,height=480,top=${screen.height-200},left=${screen.width-640}`);
+    let win = window.open("", "Save", `toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=640,height=480,top=${screen.height-200},left=${screen.width-640}`);
     win.document.body.innerHTML = `<style>body { background:${dotgrid.theme.active.background}}</style>${dotgrid.renderer.to_svg()}`;
   }
 
@@ -132,7 +134,7 @@ function Dotgrid(width,height,grid_x,grid_y,block_x,block_y)
     this.tool.settings.size.height = size.height
 
     try{
-      var win = require('electron').remote.getCurrentWindow();
+      let win = require('electron').remote.getCurrentWindow();
       win.setSize((size.width+100)*scale,(size.height+100+(interface ? 10 : 0))*scale,true);  
     }
     catch(err){
@@ -182,7 +184,7 @@ function Dotgrid(width,height,grid_x,grid_y,block_x,block_y)
 
   this.refresh = function()
   {
-    var size = {width:step(window.innerWidth-90,15),height:step(window.innerHeight-120,15)}
+    let size = {width:step(window.innerWidth-90,15),height:step(window.innerHeight-120,15)}
 
     dotgrid.tool.settings.size.width = size.width
     dotgrid.tool.settings.size.height = size.height
@@ -205,11 +207,11 @@ function Dotgrid(width,height,grid_x,grid_y,block_x,block_y)
     e.preventDefault();
     e.stopPropagation();
 
-    var file = e.dataTransfer.files[0];
+    let file = e.dataTransfer.files[0];
 
     if(!file.path || file.path.indexOf(".dot") < 0 && file.path.indexOf(".grid") < 0){ console.log("Dotgrid","Not a dot file"); return; }
 
-    var reader = new FileReader();
+    let reader = new FileReader();
     reader.onload = function(e){
       dotgrid.tool.replace(JSON.parse(e.target.result.toString().trim()));
       dotgrid.guide.refresh();
@@ -250,7 +252,7 @@ function Dotgrid(width,height,grid_x,grid_y,block_x,block_y)
   this.paste = function(e)
   {
     if(e.target !== this.picker.el){
-      var data = e.clipboardData.getData("text/source");
+      let data = e.clipboardData.getData("text/source");
       if (is_json(data)) {
         data = JSON.parse(data.trim());
         dotgrid.tool.import(data);
diff --git a/desktop/sources/scripts/generator.js b/desktop/sources/scripts/generator.js
index fdcf064..71c8f52 100644
--- a/desktop/sources/scripts/generator.js
+++ b/desktop/sources/scripts/generator.js
@@ -5,11 +5,11 @@ function Generator(layer,style)
 
   function operate(layer,offset,scale,mirror = 0,angle = 0)
   {
-    var l = copy(layer)
+    let l = copy(layer)
 
-    for(k1 in l){
-      var seg = l[k1];
-      for(k2 in seg.vertices){
+    for(let k1 in l){
+      let seg = l[k1];
+      for(let k2 in seg.vertices){
         if(mirror == 1){ seg.vertices[k2].x = (dotgrid.tool.settings.size.width) - seg.vertices[k2].x + 15 }
         if(mirror == 2){ seg.vertices[k2].y = (dotgrid.tool.settings.size.height) - seg.vertices[k2].y + 30 }
 
@@ -18,7 +18,7 @@ function Generator(layer,style)
         seg.vertices[k2].y += offset.y
 
         // Rotate
-        var center = {x:(dotgrid.tool.settings.size.width/2)+offset.x+(7.5),y:(dotgrid.tool.settings.size.height/2)+offset.y+30}
+        let center = {x:(dotgrid.tool.settings.size.width/2)+offset.x+(7.5),y:(dotgrid.tool.settings.size.height/2)+offset.y+30}
         seg.vertices[k2] = rotate_point(seg.vertices[k2],center,angle)
 
         // Scale
@@ -31,17 +31,17 @@ function Generator(layer,style)
 
   this.render = function(prev,segment,mirror = 0)
   {
-    var type = segment.type;
-    var vertices = segment.vertices;
-    var html = '';
-    var skip = 0;
+    let type = segment.type;
+    let vertices = segment.vertices;
+    let html = '';
+    let skip = 0;
 
-    for(id in vertices){
+    for(let id in vertices){
       if(skip > 0){ skip -= 1; continue; }
       
-      var vertex = vertices[id]
-      var next = vertices[parseInt(id)+1]
-      var after_next = vertices[parseInt(id)+2]
+      let vertex = vertices[id]
+      let next = vertices[parseInt(id)+1]
+      let after_next = vertices[parseInt(id)+2]
 
       if(id == 0 && !prev || id == 0 && prev && (prev.x != vertex.x || prev.y != vertex.y)){
         html += `M${vertex.x},${vertex.y} `  
@@ -51,11 +51,11 @@ function Generator(layer,style)
         html += `L${vertex.x},${vertex.y} `;  
       }
       else if(type == "arc_c"){ 
-        var clock = mirror > 0 ? '0,0' : '0,1'
+        let clock = mirror > 0 ? '0,0' : '0,1'
         html += next ? `A${Math.abs(next.x - vertex.x)},${Math.abs(next.y - vertex.y)} 0 ${clock} ${next.x},${next.y} ` : ''; 
       }
       else if(type == "arc_r"){ 
-        var clock = mirror > 0 ? '0,1' : '0,0'
+        let clock = mirror > 0 ? '0,1' : '0,0'
         html += next ? `A${Math.abs(next.x - vertex.x)},${Math.abs(next.y - vertex.y)} 0 ${clock} ${next.x},${next.y} ` : ''; 
       }
       else if(type == "bezier"){ 
@@ -76,10 +76,10 @@ function Generator(layer,style)
 
   this.convert = function(layer,mirror,angle)
   {
-    var s = ""
-    var prev = null
-    for(id in layer){
-      var seg = layer[id];
+    let s = ""
+    let prev = null
+    for(let id in layer){
+      let seg = layer[id];
       s += `${this.render(prev,seg,mirror)}`
       prev = seg.vertices ? seg.vertices[seg.vertices.length-1] : null
     }
@@ -89,7 +89,7 @@ function Generator(layer,style)
 
   this.toString = function(offset = {x:0,y:0}, scale = 1, mirror = this.style && this.style.mirror_style ? this.style.mirror_style : 0)
   {
-    var s = this.convert(operate(this.layer,offset,scale))
+    let s = this.convert(operate(this.layer,offset,scale))
 
     if(mirror == 1 || mirror == 2){
       s += this.convert(operate(this.layer,offset,scale,mirror),mirror)
diff --git a/desktop/sources/scripts/guide.js b/desktop/sources/scripts/guide.js
index ea88690..d0a12be 100644
--- a/desktop/sources/scripts/guide.js
+++ b/desktop/sources/scripts/guide.js
@@ -48,7 +48,7 @@ function Guide()
 
   this.resize = function(size)
   {
-    var offset = 15
+    let offset = 15
     this.el.width = (size.width+offset)*this.scale;
     this.el.height = (size.height+(offset*2))*this.scale;
     this.el.style.width = (size.width+offset)+"px";
@@ -61,10 +61,10 @@ function Guide()
   {
     if(!this.show_extras){ return; }
 
-    for(segment_id in dotgrid.tool.layer()){
-      var segment = dotgrid.tool.layer()[segment_id];
-      for(vertex_id in segment.vertices){
-        var vertex = segment.vertices[vertex_id];
+    for(let segment_id in dotgrid.tool.layer()){
+      let segment = dotgrid.tool.layer()[segment_id];
+      for(let vertex_id in segment.vertices){
+        let vertex = segment.vertices[vertex_id];
         this.draw_handle(vertex);
       }
     }
@@ -72,7 +72,7 @@ function Guide()
 
   this.draw_vertices = function()
   {
-    for(id in dotgrid.tool.vertices){
+    for(let id in dotgrid.tool.vertices){
       this.draw_vertex(dotgrid.tool.vertices[id]);
     }
   }
@@ -81,14 +81,14 @@ function Guide()
   {
     if(!this.show_extras){ return; }
 
-    var cursor = {x:parseInt(dotgrid.cursor.pos.x/dotgrid.grid_width),y:parseInt(dotgrid.cursor.pos.y/dotgrid.grid_width)}
+    let cursor = {x:parseInt(dotgrid.cursor.pos.x/dotgrid.grid_width),y:parseInt(dotgrid.cursor.pos.y/dotgrid.grid_width)}
 
-    for (var x = dotgrid.grid_x-1; x >= 0; x--) {
-      for (var y = dotgrid.grid_y; y >= 0; y--) {
-        var is_step = x % dotgrid.block_x == 0 && y % dotgrid.block_y == 0;
+    for (let x = dotgrid.grid_x-1; x >= 0; x--) {
+      for (let y = dotgrid.grid_y; y >= 0; y--) {
+        let is_step = x % dotgrid.block_x == 0 && y % dotgrid.block_y == 0;
 
         // Color
-        var color = is_step ? dotgrid.theme.active.f_med : dotgrid.theme.active.f_low;
+        let color = is_step ? dotgrid.theme.active.f_med : dotgrid.theme.active.f_low;
         if((y == 0 || y == dotgrid.grid_y) && cursor.x == x+1){ color = dotgrid.theme.active.f_high; }
         else if((x == 0 || x == dotgrid.grid_x-1) && cursor.y == y+1){ color = dotgrid.theme.active.f_high; }
         else if(cursor.x == x+1 && cursor.y == y+1){ color = dotgrid.theme.active.f_high; }
@@ -103,7 +103,7 @@ function Guide()
 
   this.draw_marker = function(pos,radius = 1,color)
   {
-    var ctx = this.el.getContext('2d');
+    let ctx = this.el.getContext('2d');
     ctx.beginPath();
     ctx.lineWidth = 2;
     ctx.arc(pos.x * this.scale, pos.y * this.scale, radius, 0, 2 * Math.PI, false);
@@ -114,7 +114,7 @@ function Guide()
 
   this.draw_vertex = function(pos, radius = 5)
   {
-    var ctx = this.el.getContext('2d');
+    let ctx = this.el.getContext('2d');
     ctx.beginPath();
     ctx.lineWidth = 2;
     ctx.arc((pos.x * this.scale), (pos.y * this.scale), radius, 0, 2 * Math.PI, false);
@@ -125,7 +125,7 @@ function Guide()
 
   this.draw_handle = function(pos, radius = 6)
   {
-    var ctx = this.el.getContext('2d');
+    let ctx = this.el.getContext('2d');
 
     ctx.beginPath();
     ctx.lineWidth = 3;
@@ -152,8 +152,8 @@ function Guide()
 
   this.draw_path = function(path,style)
   {
-    var ctx = this.el.getContext('2d');
-    var p = new Path2D(path);
+    let ctx = this.el.getContext('2d');
+    let p = new Path2D(path);
 
     ctx.strokeStyle = style.color;
     ctx.lineWidth = style.thickness * this.scale;
@@ -175,7 +175,7 @@ function Guide()
   {   
     if(!dotgrid.cursor.translation){ return; }
 
-    var ctx = this.el.getContext('2d');
+    let ctx = this.el.getContext('2d');
     
     ctx.beginPath();
     ctx.moveTo((dotgrid.cursor.translation.from.x * this.scale),(dotgrid.cursor.translation.from.y * this.scale));
@@ -193,7 +193,7 @@ function Guide()
 
   this.draw_cursor = function(pos = dotgrid.cursor.pos,radius = dotgrid.tool.style().thickness-1)
   {
-    var ctx = this.el.getContext('2d');
+    let ctx = this.el.getContext('2d');
 
     ctx.beginPath();
     ctx.lineWidth = 3;
@@ -214,14 +214,14 @@ function Guide()
 
   this.draw_preview = function()
   {
-    var ctx = this.el.getContext('2d');
-    var operation = dotgrid.cursor.operation && dotgrid.cursor.operation.cast ? dotgrid.cursor.operation.cast : null
+    let ctx = this.el.getContext('2d');
+    let operation = dotgrid.cursor.operation && dotgrid.cursor.operation.cast ? dotgrid.cursor.operation.cast : null
 
     if(!dotgrid.tool.can_cast(operation)){ return; }
     if(operation == "close"){ return; }
 
-    var path  = new Generator([{vertices:dotgrid.tool.vertices,type:operation}]).toString({x:0,y:0},2)
-    var style = {
+    let path  = new Generator([{vertices:dotgrid.tool.vertices,type:operation}]).toString({x:0,y:0},2)
+    let style = {
       color:dotgrid.theme.active.f_med,
       thickness:2,
       strokeLinecap:"round",
diff --git a/desktop/sources/scripts/interface.js b/desktop/sources/scripts/interface.js
index 7ab91b1..8884049 100644
--- a/desktop/sources/scripts/interface.js
+++ b/desktop/sources/scripts/interface.js
@@ -14,8 +14,8 @@ function Interface()
     document.getElementById("app").appendChild(this.el);
     this.el.appendChild(dotgrid.picker.el);
     
-    var html = ""
-    var options = {
+    let html = ""
+    let options = {
       cast:{
         line: { key:"A",icon:"M60,60 L240,240" },
         arc_c: { key:"S",icon:"M60,60 A180,180 0 0,1 240,240" },
@@ -42,10 +42,10 @@ function Interface()
       }      
     }
 
-    for(type in options){
-      var tools = options[type];
-      for(name in tools){
-        var tool = tools[name];
+    for(let type in options){
+      let tools = options[type];
+      for(let name in tools){
+        let tool = tools[name];
         html += `
         <svg 
           id="option_${name}" 
@@ -91,12 +91,12 @@ function Interface()
   {
     if(this.prev_operation == dotgrid.cursor.operation && force == false){ return; }
 
-    var multi_vertices = null;
-    var segments = dotgrid.tool.layer()
-    var sum_segments = dotgrid.tool.length();
+    let multi_vertices = null;
+    let segments = dotgrid.tool.layer()
+    let sum_segments = dotgrid.tool.length();
 
-    for(id in segments){
-      if(segments[id].vertices.length > 2){ multi_vertices = true; break; }
+    for(let i in segments){
+      if(segments[i].vertices.length > 2){ multi_vertices = true; break; }
     }
 
     document.getElementById("option_line").className.baseVal = !dotgrid.tool.can_cast("line") ? "icon inactive" : "icon";
diff --git a/desktop/sources/scripts/lib/controller.js b/desktop/sources/scripts/lib/controller.js
index 89dd9ca..e2ee467 100644
--- a/desktop/sources/scripts/lib/controller.js
+++ b/desktop/sources/scripts/lib/controller.js
@@ -32,12 +32,12 @@ function Controller()
 
   this.format = function()
   {
-    var f = [];
-    var m = this.menu[this.mode];
-    for(cat in m){
-      var submenu = [];
-      for(name in m[cat]){
-        var option = m[cat][name];
+    let f = [];
+    let m = this.menu[this.mode];
+    for(let cat in m){
+      let submenu = [];
+      for(let name in m[cat]){
+        let option = m[cat][name];
         if(option.role){
           submenu.push({role:option.role})
         }
@@ -58,8 +58,8 @@ function Controller()
   this.docs = function()
   {
     console.log("Generating docs..");
-    var svg = this.generate_svg(this.format())
-    var txt = this.documentation(this.format());
+    let svg = this.generate_svg(this.format())
+    let txt = this.documentation(this.format());
     dialog.showSaveDialog((fileName) => {
       if (fileName === undefined){ return; }
       fileName = fileName.substr(-4,4) != ".svg" ? fileName+".svg" : fileName;
@@ -70,11 +70,11 @@ function Controller()
 
   this.generate_svg = function(m)
   {
-    var svg_html = "";
+    let svg_html = "";
 
-    for(id in this.layout){
-      var key = this.layout[id];
-      var acc = this.accelerator_for_key(key.name,m);
+    for(let id in this.layout){
+      let key = this.layout[id];
+      let acc = this.accelerator_for_key(key.name,m);
       svg_html += `<rect x="${key.x + 1}" y="${key.y + 1}" width="${key.width - 2}" height="${key.height - 2}" rx="4" ry="4" title="${key.name}" stroke="#ccc" fill="none" stroke-width="1"/>`;
       svg_html += `<rect x="${key.x + 3}" y="${key.y + 3}" width="${key.width - 6}" height="${key.height - 12}" rx="3" ry="3" title="${key.name}" stroke="${acc.basic ? '#000' : acc.ctrl ? '#ccc' : '#fff'}" fill="${acc.basic ? '#000' : acc.ctrl ? '#ccc' : '#fff'}" stroke-width="1"/>`;
       svg_html += `<text x="${key.x + 10}" y="${key.y + 20}" font-size='11' font-family='Input Mono' stroke-width='0' fill='${acc.basic ? '#fff' : '#000'}'>${key.name.toUpperCase()}</text>`;
@@ -86,7 +86,7 @@ function Controller()
 
   this.documentation = function()
   {
-    var txt = "";
+    let txt = "";
 
     txt += this.documentation_for_mode("default",this.menu.default);
 
@@ -99,13 +99,13 @@ function Controller()
 
   this.documentation_for_mode = function(name,mode)
   {
-    var txt = `## ${name} Mode\n\n`;
+    let txt = `## ${name} Mode\n\n`;
 
-    for(id in mode){
+    for(let id in mode){
       if(id == "*"){ continue; }
       txt += `### ${id}\n`;
-      for(name in mode[id]){
-        var option = mode[id][name];
+      for(let name in mode[id]){
+        let option = mode[id][name];
         txt += `- ${name}: \`${option.accelerator}\`\n`;
       }
       txt += "\n"
@@ -116,11 +116,11 @@ function Controller()
 
   this.accelerator_for_key = function(key,menu)
   {
-    var acc = {basic:null,ctrl:null}
-    for(cat in menu){
-      var options = menu[cat];
-      for(id in options.submenu){
-        var option = options.submenu[id]; if(option.role){ continue; }
+    let acc = {basic:null,ctrl:null}
+    for(let cat in menu){
+      let options = menu[cat];
+      for(let id in options.submenu){
+        let option = options.submenu[id]; if(option.role){ continue; }
         acc.basic = (option.accelerator.toLowerCase() == key.toLowerCase()) ? option.label.toUpperCase().replace("TOGGLE ","").substr(0,8).trim() : acc.basic;
         acc.ctrl = (option.accelerator.toLowerCase() == ("CmdOrCtrl+"+key).toLowerCase()) ? option.label.toUpperCase().replace("TOGGLE ","").substr(0,8).trim() : acc.ctrl;
       }
diff --git a/desktop/sources/scripts/lib/theme.js b/desktop/sources/scripts/lib/theme.js
index a3b3180..a6dbbf9 100644
--- a/desktop/sources/scripts/lib/theme.js
+++ b/desktop/sources/scripts/lib/theme.js
@@ -1,6 +1,6 @@
 function Theme()
 {
-  var app = this;
+  let app = this;
 
   this.el = document.createElement("style");
   this.el.type = 'text/css';
@@ -17,7 +17,7 @@ function Theme()
 
   this.load = function(t, fall_back)
   {
-    var theme = is_json(t) ? JSON.parse(t).data : t.data;
+    let theme = is_json(t) ? JSON.parse(t).data : t.data;
 
     if(!theme || !theme.background){
       if(fall_back) {
@@ -27,7 +27,7 @@ function Theme()
       }
     }
 
-    var css = `
+    let css = `
     :root {
       --background: ${theme.background};
       --f_high: ${theme.f_high};
@@ -62,11 +62,11 @@ function Theme()
     e.preventDefault();
     e.stopPropagation();
 
-    var file = e.dataTransfer.files[0];
+    let file = e.dataTransfer.files[0];
 
     if(!file.name || !file.name.indexOf(".thm") < 0){ console.log("Theme","Not a theme"); return; }
 
-    var reader = new FileReader();
+    let reader = new FileReader();
     reader.onload = function(e){
       app.load(e.target.result);
     };
diff --git a/desktop/sources/scripts/picker.js b/desktop/sources/scripts/picker.js
index 7f6d3ac..04cdfe4 100644
--- a/desktop/sources/scripts/picker.js
+++ b/desktop/sources/scripts/picker.js
@@ -32,7 +32,7 @@ function Picker()
 
   this.validate = function()
   {
-    var parts = this.parse(this.el.value)
+    let parts = this.parse(this.el.value)
 
     if(parts.color){ this.set_color(parts.color); }
     if(parts.size){ this.set_size(parts.size); }
@@ -70,7 +70,7 @@ function Picker()
 
   this.update = function()
   {
-    var parts = this.parse(this.el.value)
+    let parts = this.parse(this.el.value)
     if(!parts.color){ return; }
 
     dotgrid.tool.style().color = parts.color;
@@ -91,12 +91,12 @@ function Picker()
 
   this.parse = function(value)
   {
-    var parts = value.split(" ");
-    var color = null;
-    var size = null;
+    let parts = value.split(" ");
+    let color = null;
+    let size = null;
 
-    for(id in parts){
-      var part = parts[id];
+    for(let id in parts){
+      let part = parts[id];
       if(is_color(part) && !color){ color = part; }
       if(is_size(part) && !size){ size = { width:parseInt(part.toLowerCase().split("x")[0]),height:parseInt(part.toLowerCase().split("x")[1]) }; }
     }
@@ -116,7 +116,7 @@ function Picker()
       return false
     }
 
-    var re = /\#[0-9A-Fa-f]/g;
+    let re = /\#[0-9A-Fa-f]/g;
     return re.test(val)
   }
 
diff --git a/desktop/sources/scripts/renderer.js b/desktop/sources/scripts/renderer.js
index deffa3c..c801ca1 100644
--- a/desktop/sources/scripts/renderer.js
+++ b/desktop/sources/scripts/renderer.js
@@ -23,8 +23,8 @@ function Renderer()
     this.svg_el.style.height = dotgrid.tool.settings.size.height+(10);
     this.svg_el.style.strokeWidth = dotgrid.tool.style().thickness;
 
-    var styles = dotgrid.tool.styles
-    var paths = dotgrid.tool.paths()
+    let styles = dotgrid.tool.styles
+    let paths = dotgrid.tool.paths()
 
     this.layer_1.style.strokeWidth = styles[0].thickness;
     this.layer_1.style.strokeLinecap = styles[0].strokeLinecap;
@@ -54,22 +54,22 @@ function Renderer()
 
     this.refresh();
 
-    var xml = new XMLSerializer().serializeToString(this.svg_el);
-    var svg64 = btoa(xml);
-    var b64Start = 'data:image/svg+xml;base64,';
-    var image64 = b64Start + svg64;
-    var img = new Image;
+    let xml = new XMLSerializer().serializeToString(this.svg_el);
+    let svg64 = btoa(xml);
+    let b64Start = 'data:image/svg+xml;base64,';
+    let image64 = b64Start + svg64;
+    let img = new Image;
 
-    var canvas = document.createElement("canvas");
+    let canvas = document.createElement("canvas");
 
     canvas.width = (size.width)*2; 
     canvas.height = (size.height+30)*2;
 
-    var ctx = canvas.getContext('2d');
+    let ctx = canvas.getContext('2d');
 
     img.onload = function(){
       ctx.drawImage(img, 0, 0, (size.width)*2, (size.height+30)*2);
-      var data = canvas.toDataURL('image/png').replace(/^data:image\/\w+;base64,/, "");
+      let data = canvas.toDataURL('image/png').replace(/^data:image\/\w+;base64,/, "");
       dotgrid.renderer.to_png_ready(callback, new Buffer(data, 'base64'),size)
     };
     img.src = image64;
@@ -84,16 +84,16 @@ function Renderer()
   {
     this.refresh();
 
-    var xml = new XMLSerializer().serializeToString(this.svg_el);
-    var svg64 = btoa(xml);
-    var b64Start = 'data:image/svg+xml;base64,';
-    var image64 = b64Start + svg64;
+    let xml = new XMLSerializer().serializeToString(this.svg_el);
+    let svg64 = btoa(xml);
+    let b64Start = 'data:image/svg+xml;base64,';
+    let image64 = b64Start + svg64;
 
-    var canvas = document.createElement("canvas");
-    var ctx = canvas.getContext('2d');
+    let canvas = document.createElement("canvas");
+    let ctx = canvas.getContext('2d');
     
-    var win = window.open('about:blank','image from canvas');
-    var img = new Image;
+    let win = window.open('about:blank','image from canvas');
+    let img = new Image;
 
     canvas.width = size.width*2; 
     canvas.height = size.height*2;
diff --git a/desktop/sources/scripts/tool.js b/desktop/sources/scripts/tool.js
index d88360e..ba76359 100644
--- a/desktop/sources/scripts/tool.js
+++ b/desktop/sources/scripts/tool.js
@@ -102,10 +102,10 @@ function Tool()
 
   this.remove_segments_at = function(pos)
   {
-    for(segment_id in this.layer()){
-      var segment = this.layer()[segment_id];
-      for(vertex_id in segment.vertices){
-        var vertex = segment.vertices[vertex_id];
+    for(let segment_id in this.layer()){
+      let segment = this.layer()[segment_id];
+      for(let vertex_id in segment.vertices){
+        let vertex = segment.vertices[vertex_id];
         if(Math.abs(pos.x) == Math.abs(vertex.x) && Math.abs(pos.y) == Math.abs(vertex.y)){
           segment.vertices.splice(vertex_id,1)
         }
@@ -128,10 +128,10 @@ function Tool()
 
   this.vertex_at = function(pos)
   {
-    for(segment_id in this.layer()){
-      var segment = this.layer()[segment_id];
-      for(vertex_id in segment.vertices){
-        var vertex = segment.vertices[vertex_id];
+    for(let segment_id in this.layer()){
+      let segment = this.layer()[segment_id];
+      for(let vertex_id in segment.vertices){
+        let vertex = segment.vertices[vertex_id];
         if(vertex.x == Math.abs(pos.x) && vertex.y == Math.abs(pos.y)){
           return vertex;
         }
@@ -145,7 +145,7 @@ function Tool()
     if(!this.layer()){ this.layers[this.index] = []; }
     if(!this.can_cast(type)){ console.warn("Cannot cast"); return; }
 
-    var append_target = this.can_append({type:type,vertices:this.vertices.slice()})
+    let append_target = this.can_append({type:type,vertices:this.vertices.slice()})
 
     if(append_target){
       this.layers[this.index][append_target].vertices = this.layers[this.index][append_target].vertices.concat(this.vertices.slice())
@@ -168,12 +168,12 @@ function Tool()
   this.toggle = function(type,mod = 1)
   {
     if(type == "linecap"){
-      var a = ["butt","square","round"];
+      let a = ["butt","square","round"];
       this.i.linecap += mod;
       this.style().strokeLinecap = a[this.i.linecap % a.length];
     }
     else if(type == "linejoin"){
-      var a = ["miter","round","bevel"];
+      let a = ["miter","round","bevel"];
       this.i.linejoin += mod;
       this.style().strokeLinejoin = a[this.i.linejoin % a.length];
     }
@@ -211,8 +211,8 @@ function Tool()
 
   this.can_append = function(content)
   {
-    for(id in this.layer()){
-      var stroke = this.layer()[id];
+    for(let id in this.layer()){
+      let stroke = this.layer()[id];
       if(stroke.type != content.type){ continue; }
       if(!stroke.vertices){ continue; }
       if(!stroke.vertices[stroke.vertices.length-1]){ continue; }
@@ -228,7 +228,7 @@ function Tool()
     if(!type){ return false; }
     // Cannot cast close twice
     if(type == "close"){
-      var prev = this.layer()[this.layer().length-1];
+      let prev = this.layer()[this.layer().length-1];
       if(!prev || prev.type == "close"){
         return false;
       }
@@ -243,9 +243,9 @@ function Tool()
 
   this.paths = function()
   {
-    var l1 = new Generator(dotgrid.tool.layers[0],dotgrid.tool.styles[0]).toString({x:-10,y:-10},1)
-    var l2 = new Generator(dotgrid.tool.layers[1],dotgrid.tool.styles[1]).toString({x:-10,y:-10},1)
-    var l3 = new Generator(dotgrid.tool.layers[2],dotgrid.tool.styles[2]).toString({x:-10,y:-10},1)
+    let l1 = new Generator(dotgrid.tool.layers[0],dotgrid.tool.styles[0]).toString({x:-10,y:-10},1)
+    let l2 = new Generator(dotgrid.tool.layers[1],dotgrid.tool.styles[1]).toString({x:-10,y:-10},1)
+    let l3 = new Generator(dotgrid.tool.layers[2],dotgrid.tool.styles[2]).toString({x:-10,y:-10},1)
 
     return [l1,l2,l3]
   }
@@ -257,10 +257,10 @@ function Tool()
 
   this.translate = function(a,b)
   {
-    for(segment_id in this.layer()){
-      var segment = this.layer()[segment_id];
-      for(vertex_id in segment.vertices){
-        var vertex = segment.vertices[vertex_id];
+    for(let segment_id in this.layer()){
+      let segment = this.layer()[segment_id];
+      for(let vertex_id in segment.vertices){
+        let vertex = segment.vertices[vertex_id];
         if(vertex.x == Math.abs(a.x) && vertex.y == Math.abs(a.y)){
           segment.vertices[vertex_id] = {x:Math.abs(b.x),y:Math.abs(b.y)};
         }
@@ -273,12 +273,12 @@ function Tool()
 
   this.translate_multi = function(a,b)
   {
-    var offset = {x:a.x - b.x,y:a.y - b.y}
+    let offset = {x:a.x - b.x,y:a.y - b.y}
 
-    for(segment_id in this.layer()){
-      var segment = this.layer()[segment_id];
-      for(vertex_id in segment.vertices){
-        var vertex = segment.vertices[vertex_id];
+    for(let segment_id in this.layer()){
+      let segment = this.layer()[segment_id];
+      for(let vertex_id in segment.vertices){
+        let vertex = segment.vertices[vertex_id];
         segment.vertices[vertex_id] = {x:vertex.x-offset.x,y:vertex.y-offset.y};
       }
     }
diff --git a/index.html b/index.html
index 70be766..5494334 100644
--- a/index.html
+++ b/index.html
@@ -28,7 +28,7 @@
   <body>
     <div id="app">
       <script>
-        var dialog = null;
+        let dialog = null;
         dotgrid = new Dotgrid(300,300,20,20,4,4);
         dotgrid.install();
       </script>
diff --git a/web/events.js b/web/events.js
index 668b572..fc032ab 100644
--- a/web/events.js
+++ b/web/events.js
@@ -1,6 +1,6 @@
 document.onkeyup = (e) =>
 {
-  var ch = e.key.toLowerCase();
+  let ch = e.key.toLowerCase();
 
   if(e.target && e.target.id == "picker"){ return; }