1000 REM TWO-D MAP SEARCH (With Music and Menu Screen)
1100 SND% = 1                   'Turn sound on
1110 PJT% = 0                   'Projection is planar
1170 GOSUB 4200                 'Display menu screen
1180 IF Q$ = "X" THEN GOTO 1250 'Exit immediately on command

2450 IF QM% > 0 THEN GOTO 2490  'Skip tests when not in search mode

2640 IF QM% > 0 THEN GOTO 2730  'Not in search mode
2650    O% = 2 + INT((OMAX% - 1) * RND)
2660    CODE$ = CHR$(59 + 4 * D% + O%)
2680    GOSUB 4700              'Get value of M%

3530 IF D% > 1 THEN DUR = 2 ^ INT(.5 * (YH - YL) / (YNEW - 9 * YL / 8 + YH / 8))

3610 IF ASC(Q$) > 96 THEN Q$ = CHR$(ASC(Q$) - 32)   'Convert to upper case
3630 IF Q$ = "" OR INSTR("ADIPSX", Q$) = 0 THEN GOSUB 4200
3640 IF Q$ = "A" THEN T% = 1: QM% = 0
3680 IF Q$ = "D" THEN D% = 1 + (D% MOD 2): T% = 1
3730 IF Q$ = "I" THEN IF T% <> 1 THEN SCREEN 0: WIDTH 80: COLOR 15, 1: CLS : LINE INPUT "Code? "; CODE$: IF CODE$ = "" THEN Q$ = " ": CLS :  ELSE T% = 1: QM% = 1: GOSUB 4700
3790 IF Q$ = "X" THEN T% = 0

4200 REM Display menu screen
4210 SCREEN 0: WIDTH 80: COLOR 15, 1: CLS
4220 WHILE Q$ = "" OR INSTR("AIX", Q$) = 0
4230    LOCATE 1, 27: PRINT "STRANGE ATTRACTOR PROGRAM"
4260    PRINT : PRINT
4270    PRINT TAB(27); "A: Search for attractors"
4300    PRINT TAB(27); "D: System is"; STR$(D%); "-D polynomial map"
4370    PRINT TAB(27); "I: Input code from keyboard"
4400    PRINT TAB(27); "P: Projection is ";
4410        IF PJT% = 0 THEN PRINT "planar   "
4420        IF PJT% = 1 THEN PRINT "spherical"
4540    PRINT TAB(27); "S: Sound is ";
4550        IF SND% = 0 THEN PRINT "off"
4560        IF SND% = 1 THEN PRINT "on "
4600    PRINT TAB(27); "X: Exit program"
4610    Q$ = INKEY$
4620    IF Q$ <> "" THEN GOSUB 3600     'Respond to user command
4630 WEND
4640 RETURN

4700 REM Get dimension and order
4710 D% = 1 + INT((ASC(LEFT$(CODE$, 1)) - 65) / 4)
4740 O% = 2 + (ASC(LEFT$(CODE$, 1)) - 65) MOD 4
4750 M% = 1: FOR I% = 1 TO D%: M% = M% * (O% + I%): NEXT I%
4770 IF LEN(CODE$) = M% + 1 OR QM% <> 1 THEN GOTO 4810
4780    BEEP        'Illegal code warning
4790    WHILE LEN(CODE$) < M% + 1: CODE$ = CODE$ + "M": WEND
4800    IF LEN(CODE$) > M% + 1 THEN CODE$ = LEFT$(CODE$, M% + 1)
4810 RETURN