1next=0:max=5
    2DIM lastx(max),lasty(max)
    3FOR I%=0 TO max:lastx(I%)=0:lasty(I%)=0:NEXT
   10moveabs=4
   20linerel=1
   30TRIrel=linerel+80
   40moverel=0
   50DIM ox 3,oy 3
   60DIM Code 511
   70PROCassemble
   80PROC_init
   90PROC_main
  100END
  110DEFPROC_cursor
  120   MOVE OX,OY
  130   VDU 128
  140ENDPROC
  150 
  160DEFPROC_init
  170OX = 0:OY = 0:X = 0:Y = 0:!ox=OX:!oy=OY
  180MODE1
  190   VDU 5,18,3,1,23,128,0,24,60,126,24,24,24,0
  200ENDPROC
  210 
  220DEFPROC_track
  221LOCAL I%
  230   X=ADVAL(1): Y=ADVAL(2)
  240   X = (1024 - (X DIV 64)) * 1280 DIV 1024: Y = Y DIV 64
  250   X = X DIV 16 * 16: Y = Y DIV 20 * 20
  260lastx(next)=X:lasty(next)=Y
  261X=0:Y=0
  262next=(next+1) MOD (max+1)
  270FOR I%=0 TO max
  280   X=X+lastx(I%)
  290   Y=Y+lasty(I%)
  300NEXT
  310X=X DIV (max+1): Y=Y DIV (max+1)
  320ENDPROC
  330 
  340DEFPROC_main
  341down=FALSE
  350   REPEAT
  360      A%=USR(cursor)
  370      !ox = X:!oy = Y
  380      REPEAT PROC_track
  390      IF ((ADVAL(0) AND 1) <> 0) AND (NOT down) THEN A%=USR(cursor):down=TRUE
  391IF((ADVAL(0) AND 1) = 0) THEN down=FALSE
  392UNTIL X<>!ox OR Y<>!oy
  400      A%=USR(cursor)
  410      !ox = X:!oy = Y
  420   UNTIL FALSE
  430ENDPROC
  440DEFPROCassemble
  450FOR Pass=0 TO 2 STEP 2
  460OSWRCH=&FFEE
  470P%=Code
  480[OPT Pass
  490.cursor
  500]
  510PROCplot(moveabs):PROCvar(ox):PROCvar(oy)
  520PROCplot(linerel):PROCconst(50):PROCconst(0)
  530PROCplot(linerel):PROCconst(0):PROCconst(-50)
  540PROCplot(linerel):PROCconst(-50):PROCconst(0)
  550PROCplot(linerel):PROCconst(0):PROCconst(50)
  560   [OPT Pass:Rts:]
  570NEXT Pass
  580ENDPROC
  590 
  600DEFPROCvar(Addr)
  610[OPT Pass
  620   Lda Addr
  630   Jsr OSWRCH
  640   Lda Addr+1
  650   Jsr OSWRCH
  660]
  670ENDPROC
  680 
  690DEFPROCvdu(C%)
  700[OPT Pass
  710   Lda #C%
  720   Jsr OSWRCH
  730]
  740ENDPROC
  750 
  760DEFPROCplot(plotcode)
  770   PROCvdu(25)
  780   PROCvdu(plotcode)
  790ENDPROC
  800 
  810DEFPROCconst(X%)
  820X% = (X% AND &FFFF)
  830   PROCvdu(X% MOD 256)
  840   PROCvdu(X% DIV 256)
  850ENDPROC