10 ' AMAZIN -- DRAW A MAZE UP TO 14 BY 21
  20 ' EDUSYSTEM 50 REFACTORING BY RENAUD FIVET
  90 DEF FNR(R)=INT(RND(1)*R+1)
 100 RANDOMIZE
 110 DIM V(13,20)
 120 PRINT "WHAT ARE YOUR WIDTH AND LENGTH";\ INPUT H,V
 122 PRINT
 130 IF H<2 THEN 132\ IF H>14 THEN 132
 131 IF V<2 THEN 132\ IF V<=21 THEN 150
 132 PRINT "MEANINGLESS DIMENSIONS, TRY AGAIN"
 140 PRINT
 141 GOTO 120
 150 PRINT
 151 PRINT
 160 ' PICK ENTRY CELL ON TOP ROW AND DRAW UPPER WALL
 161 C=H*V        ' COUNT OF CELLS LEFT TO FILL
 162 R=FNR(H)-1   ' R,0 TOP ENTRY CELL COORD
 163 H=H-1\ V=V-1 ' COORD IN 0..H,0..V
 170 FOR I=0 TO H
 171  IF I=R THEN 174
 172   PRINT ":--";
 173   GOTO 175
 174  PRINT ":  ";
 175 NEXT I
 185 PRINT ":"
 187 ' PICK EXIT CELL ON BOTTOM ROW AS CURRENT
 190 R=FNR(H+1)-1\ S=V ' R,S CURRENT CELL COORD
 192 V(R,S)=2
 193 C=C-1
 202 GOTO 260
 209 ' SCAN FOR NEXT POSITION TO CHECK
 210 R=R+1
 215 IF R<=H THEN 250
 220  R=0\ S=S+1
 225  IF S<=V THEN 250
 230   S=0
 250 IF V(R,S)=0 THEN 210
 255 ' CHECK FOR ADJACENT UNMARKED CELLS AND PICK ONE AT RANDOM
 260 IF R=0 THEN 530\ IF V(R-1,S)<>0 THEN 530 ' L?
 270 IF S=0 THEN 390\ IF V(R,S-1)<>0 THEN 390 ' LU?
 290 IF R=H THEN 330\ IF V(R+1,S)<>0 THEN 330 ' LUR?
 310  ON FNR(3) GOTO 790,820,860 ' LUR
 320 ' LU
 330 IF S=V THEN 370\ IF V(R,S+1)<>0 THEN 370 ' LUD?
 350  ON FNR(3) GOTO 790,820,910 ' LUD
 370 ON FNR(2) GOTO 790,820 ' LU
 380 ' L
 390 IF R=H THEN 470\ IF V(R+1,S)<>0 THEN 470 ' LR?
 401 IF S=V THEN 450\ IF V(R,S+1)<>0 THEN 450 ' LRD?
 430  ON FNR(3) GOTO 790,860,910 ' LRD
 450 ON FNR(2) GOTO 790,860 ' LR
 460 ' L
 470 IF S=V THEN 790\ IF V(R,S+1)<>0 THEN 790 ' LD? OR L
 500  ON FNR(2) GOTO 790,910 ' LD
 520 '
 530 IF S=0 THEN 670\ IF V(R,S-1)<>0 THEN 670 ' U?
 541 IF R=H THEN 610\ IF V(R+1,S)<>0 THEN 610 ' UR?
 550 IF S=V THEN 590\ IF V(R,S+1)<>0 THEN 590 ' URD?
 570  ON FNR(3) GOTO 820,860,910 ' URD
 590 ON FNR(2) GOTO 820,860 ' UR
 600 '
 610 IF S=V THEN 820\ IF V(R,S+1)<>0 THEN 820 ' UD? OR U
 640  ON FNR(2) GOTO 820,910 ' UD
 660 '
 670 IF R=H THEN 740\ IF V(R+1,S)<>0 THEN 740 ' R?
 681 IF S=V THEN 860\ IF V(R,S+1)<>0 THEN 860 ' RD? OR R
 710  ON FNR(2) GOTO 860,910 ' RD
 730 '
 740 IF S=V THEN 210\ IF V(R,S+1)<>0 THEN 210 ' D? OR SCAN
 770  GOTO 910 ' D
 780 '
 790 ' REMOVE LEFT WALL
 800  R=R-1
 801  V(R,S)=3
 812  GOTO 999
 820 ' REMOVE UP WALL
 830  S=S-1
 840  V(R,S)=2
 850  GOTO 999
 860 ' REMOVE RIGHT WALL
 870  IF V(R,S)<2 THEN 880
 872   V(R,S)=4
 873   GOTO 890
 880   V(R,S)=3
 890  R=R+1
 900  IF V(R,S)<>0 THEN 902\ V(R,S)=1
 902  GOTO 999
 910 ' REMOVE DOWN WALL
 922  IF V(R,S)<2 THEN 940
 930   V(R,S)=4
 931   GOTO 950
 940   V(R,S)=2
 950  S=S+1
 960  IF V(R,S)<>0 THEN 999\ V(R,S)=1
 999 C=C-1\ IF C>0 THEN 260 ' LOOP WHILE C
1000 ' DRAW MAZE
1010 FOR J=0 TO V
1011  PRINT "I";
1012  FOR I=0 TO H
1013   IF V(I,J)<3 THEN 1030
1020    PRINT "   ";
1021    GOTO 1040
1030    PRINT "  I";
1040  NEXT I
1041  PRINT
1043  FOR I=0 TO H
1045  IF V(I,J)<=1 THEN 1060
1050   IF V(I,J)=3 THEN 1060
1051    PRINT ":  ";
1052    GOTO 1070
1060    PRINT ":--";
1070  NEXT I
1071  PRINT ":"
1072 NEXT J
1073 END