SCREEN 13
RANDOMIZE TIMER

REM CONSTANTS AND DIMENSIONS
DIM P(4, 150, 2)
PI = 3.141592654#
CX = 160
CY = 100
RM = 90
isStart = 0

3310 REM  ART FORMS 20-22
3320 RS = 0: EL = 1: SL = RND(1) * .5: GOTO 3350
3330 SL = RND(1) * .4 + .4: EL = SL: RS = RND(1) * (.8 - SL): GOTO 3350
3340 SL = RND(1): EL = RND(1): RS = (1 - SL) * RND(1) * .8: IF ABS(EL - SL) < .3 GOTO 3340
3350 NS = INT(RND(1) * 8 + 5)
3360 OV = INT(RND(1) * 2 + 1)
3370 NA = INT((RND(1) * 41 + 120) / NS)
3380 NR = OV * NA / ((INT(NA / OV) * OV + 1) * NS)
3390 GOTO 3540
3400 RS = RND(1) * .5: SL = RND(1) * .36 + .04: EL = SL
3410 NS = INT(RND(1) * 6 + 5)
3420 NR = (1 - EL - RS) / (NS * (SL + 4 / RM))
3430 NA = INT(NR * (RND(1) * 41 + 100))
3440 GOTO 3540
3450 IF RND(1) - .5 > 0 THEN RS = 0: GOTO 3470
3460 RS = RND(1) * .2 + .1
3470 SL = RND(1) * .04 + .06
3480 IF RND(1) - .5 > 0 THEN EL = SL: GOTO 3500
3490 EL = RND(1) * SL * .5
3500 NR = RND(1) * 31 + 20
3510 NA = INT(RND(1) * 31 + 40)
3520 NS = INT(500 / NA)
3530 IF ABS(NR / NS - INT(NR / NS)) < .1 GOTO 3500
3540 GOSUB chooseColor
3550 REM  GRAPH ROUTINE
3560 DI = SGN(RND(1) - .5)
3570 IA = 2 * PI * NR / NA * DI
3580 FOR I = 0 TO NS - 1
3590 ISR = RM * (1 - EL - RS) / NA
3600 ILR = RM * (1 - RS - SL) / NA
3610 IF NN = 9 OR NN = 27 OR NN = 19 THEN ISR = ISR * 2: ILR = ILR * 2
3620 LR = RM * (RS + SL): SR = RM * RS
3630 AN = I * 2 * PI / NS * DI
3640 IF NN = 9 OR NN = 27 OR NN = 19 THEN AN = AN - PI * DI / NS
3650 FOR J = 0 TO NA
3660 CA = COS(AN): SA = SIN(AN)
3670 LINE (CX + SR * SA, CY - SR * CA)-(CX + LR * SA, CY - LR * CA): GOSUB Pause
3680 AN = AN + IA: LR = LR + ILR: SR = SR + ISR
3690 IF LR > RM + ILR / 4 AND NA - INT(NA / 2) * 2 = 0 THEN ILR = -ILR: LR = LR + 2 * ILR: ISR = -ISR: SR = SR + 2 * ISR
3700 IF LR > RM + ILR / 4 THEN ILR = -ILR: LR = LR + ILR: ISR = -ISR: SR = SR + ISR
3710
3720 NEXT J
3730 NEXT I
3740 GOSUB Pause: GOTO 3310

Pause:
FOR j1 = 1 TO 10000
    IF INKEY$ <> "" THEN
        GOTO endProgram
    END IF
NEXT
RETURN

chooseColor:
IF RND - .5 > 0 THEN
    COLOR 7
ELSE
    IF RND - .5 > 0 OR isStart = 0 THEN
        COLOR 4
    ELSE
        COLOR 0
    END IF
END IF
'CLS
isStart = 1
RETURN

endProgram:
COLOR 7
END

' TODO:
'  remove linenumbers
'  more colors