diff --git a/TODO b/TODO
index bff4321..6afe7e0 100644
--- a/TODO
+++ b/TODO
@@ -44,3 +44,17 @@ List some shell linters somewhere.
 
 * ShellCheck
 * checkbashisms
+
+
+Set parallel and series
+----------
+I want to be able to make only some directories run in series.
+
+* Rename .urchin to .urchin_root.
+* Look for a .urchin_dir file.
+* If .urchin_dir contains "series", run that directory in series rather
+  than in parallel.
+
+Rename to something other than "test"?
+----------
+Maybe wait until I have a use for this.