100 REM BASIC Month 6: The Mandelbaum Set
110 REM http://reddit.com/r/RetroBattlestations
120 REM originallay written by FozzTexx
130 REM Turbo-BASIC XL version by /u/papa_robot

200 REM === Initialize variables and constants
210 PI=3.14159265:DIM PT(128):DIM GO(8),CM(8):DIM SZ(23*20),RZ(2),NT(8),NM(8),OM(8)
220 GO(0)=33:GO(1)=138:GO(2)=200
230 CM(0)=1:CM(1)=0:CM(2)=0
240 CM(3)=0:CM(4)=1:CM(5)=0
250 CM(6)=0:CM(7)=0:CM(8)=1
260 GW=GO(2)*GO(2)/GO(1)
270 TH=GO(2)+5:EXEC DLOAD:TH=TH+SZ(1)
280 RZ(0)=319:RZ(1)=189:REM Width & height of screen
290 SX=(RZ(0)-RZ(0)*0.05)/GW:SY=(RZ(1)-RZ(1)*0.07)/TH
300 SK=SX:IF SY<SK THEN SK=SY

310 GRAPHICS 8+16:SETCOLOR 2,0,0:SETCOLOR 1,1,14:COLOR 1:POKE 77,0
320 REM DRAW "It's"
330 X=-GW/2:Y=-GO(2)/2:EXEC TRANSLATE:REM Translate
340 X=SK:Y=SK:EXEC SCALE:REM Scale
350 X=RZ(0)/2:Y=RZ(1)/2:EXEC TRANSLATE:REM Translate
360 EXEC MSAVE
370 RESTORE :REM Reset reading of DATA back to first object
380 EXEC DLOAD:EXEC DRAWP
390 EXEC DLOAD
400 X=(GW-SZ(0))*SK:Y=(GO(2)+SZ(1)+5)*SK
410 EXEC TRANSLATE:EXEC DRAWP:EXEC MRESTORE
420 EXEC DLOAD
430 GX=GO(1)/2:GY=GO(2)/2:GB=GY-GX:OO=GO(2)*GO(2)/GO(1)-GO(1)
440 EXEC G

500 REM "Step aside, string bean."
510 X=-RZ(0)/2:Y=-RZ(1)/2:EXEC TRANSLATE:REM Translate
520 A=PI/2:EXEC ROTATE:REM Rotate
530 X=GO(1)/GO(2):Y=X:EXEC SCALE:REM Scale
540 X=RZ(0)/2+(GW/2-GO(1)/2)*SK:Y=RZ(1)/2:EXEC TRANSLATE:REM Translate
550 EXEC G
560 IF HT>1 THEN GOTO 510
570 EXEC O

998 IF PEEK($D01F)<>6 THEN 998: REM wait until START is pressed
999 END

1000 REM === Update current transformation matrix
1010 REM - Input: 3x3 matrix in 1D array NT
1020 REM - Updates 3x3 Matrix in 1D array CM
1025 PROC UPDATE
1030   FOR R=0 TO 2:FOR C=0 TO 2
1040       NM(R*3+C)=0
1050       FOR K=0 TO 2
1060         NM(R*3+C)=NM(R*3+C)+NT(R*3+K)*CM(K*3+C)
1070       NEXT K:NEXT C:NEXT R
1080   FOR K=0 TO 3*3-1:CM(K)=NM(K):NEXT K
1090 ENDPROC

2000 REM === Translate - move origin
2010 REM - Input: X, Y
2020 REM - Updates current transformation matrix in CM
2025 PROC TRANSLATE
2030   NT(0)=1:NT(1)=0:NT(2)=X
2040   NT(3)=0:NT(4)=1:NT(5)=Y
2050   NT(6)=0:NT(7)=0:NT(8)=1
2060   EXEC UPDATE
2070 ENDPROC

2100 REM === Rotate - rotate drawing space
2110 REM - Input: Angle in radians in A
2120 REM - Updates current transformation matrix in CM
2125 PROC ROTATE
2130   NT(0)=COS(A):NT(1)=-SIN(A):NT(2)=0
2140   NT(3)=-NT(1):NT(4)=NT(0):NT(5)=0
2150   NT(6)=0:NT(7)=0:NT(8)=1
2160   EXEC UPDATE
2170 ENDPROC

2200 REM === Scale - modify unit lengths of drawing
2210 REM - Input: X, Y
2220 REM - Updates current transformation matrix in CM
2225 PROC SCALE
2230   NT(0)=X:NT(1)=0:NT(2)=0
2240   NT(3)=0:NT(4)=Y:NT(5)=0
2250   NT(6)=0:NT(7)=0:NT(8)=1
2260   EXEC UPDATE
2270 ENDPROC

2300 REM === Transform single point using current transformation matrix
2310 REM - Input: X, Y
2320 REM - Returns transformed point in X and Y
2325 PROC TRANSFORM
2330   NT(0)=X:NT(1)=Y:NT(2)=1
2340   FOR R=0 TO 2
2350     NM(R)=0
2360     FOR K=0 TO 2
2370       NM(R)=NM(R)+NT(K)*CM(R*3+K)
2380     NEXT K:NEXT R
2390   X=NM(0):Y=NM(1)
2400 ENDPROC

2500 REM === Draw line
2510 REM - Input: X1,Y1 X2,Y2
2515 PROC DRAWL
2520   X=X1:Y=Y1:EXEC TRANSFORM:A1=X:B1=Y
2530   X=X2:Y=Y2:EXEC TRANSFORM:A2=X:B2=Y
2540   PLOT A1,B1:DRAWTO A2,B2
2550 ENDPROC

2600 REM === Load object from DATA
2610 REM - Reads the next object from DATA and leaves size in array SZ
2620 REM and paths in array PT
2625 PROC DLOAD
2630   ZI=0:READ ZX:SZ(0)=ZX:READ ZY:SZ(1)=ZY
2640   READ ZC:PT(ZI)=ZC:ZI=ZI+1
2650   IF ZC=0 THEN GOTO 2695
2660   FOR ZJ=1 TO ZC:READ ZX:READ ZY
2670     PT(ZI)=ZX:ZI=ZI+1:PT(ZI)=ZY:ZI=ZI+1
2680   NEXT ZJ
2690   GOTO 2640
2695 ENDPROC

2700 REM === Draw path
2710 REM - Input: paths to draw in array PT
2715 PROC DRAWP
2720   ZI=0
2730   ZC=PT(ZI):ZI=ZI+1:IF ZC=0 THEN GOTO 2795
2740   X1=PT(ZI):ZI=ZI+1:Y1=PT(ZI):ZI=ZI+1
2750   FOR ZJ=1 TO ZC-1
2760     X2=PT(ZI):ZI=ZI+1:Y2=PT(ZI):ZI=ZI+1
2770     EXEC DRAWL
2780     X1=X2:Y1=Y2:NEXT ZJ
2790   GOTO 2730
2795 ENDPROC

2800 REM == Save current transformation matrix
2810 REM Copies array CM to array OM
2815 PROC MSAVE
2820   FOR I=0 TO 8:OM(I)=CM(I):NEXT I
2830 ENDPROC

2900 REM == Restore transformation matrix
2910 REM Copies array OM to array CM
2915 PROC MRESTORE
2920   FOR I=0 TO 8:CM(I)=OM(I):NEXT I
2930 ENDPROC

3000 REM Mandelbaum arc
3010 REM - Input: Arc center at CX,CY; Start/end radians in SA,EA
3020 REM "If you want to live in a butcher shop, I'm gonna treat you like a piece of meat."
3025 PROC MANDELB
3030   IF (EA<SA) THEN EA=EA+2*PI
3040   NW=SZ(0):NH=SZ(1):NS=GO(0)/NW:SH=NH*NS
3050   RO=GO(1)/2:RI=RO-GO(0)
3060   AL=(EA-SA)*GO(1)/2:SG=INT(AL/SH)
3070   GA=(EA-SA)/SG
3080   GC=COS(2*PI-GA):GS=SIN(2*PI-GA):ZC=COS(0):ZS=SIN(0)
3090   F1=CX+RI*GC:G1=CY+RI*GS
3100   F2=CX+RO*GC:G2=CY+RO*GS
3110   F3=CX+RI*ZC:G3=CY+RI*ZS
3120   F4=CX+RO*ZC:G4=CY+RO*ZS
3130   D1=F3-F1:D2=G3-G1:D3=F4-F2:D4=G4-G2
3140   L1=SQR(D1*D1+D2*D2):L2=SQR(D3*D3+D4*D4)
3150   EXEC MSAVE
3160   X=CX:Y=CY:EXEC TRANSFORM:AX=X:AY=Y

3170   REM Walk through PT and draw
3180   FOR SN=0 TO SG-1
3190     EXEC MRESTORE
3200     X=-AX:Y=-AY:EXEC TRANSLATE:REM Translate
3210     A=2*PI-(SA+SN*GA):EXEC ROTATE:REM Rotate
3220     X=AX:Y=AY:EXEC TRANSLATE:REM Translate
3230     ZI=0
3240     ZC=PT(ZI):ZI=ZI+1:IF ZC=0 THEN GOTO 3350
3250     X1=PT(ZI)*NS:ZI=ZI+1
3260     Y1=PT(ZI)*NS*(L1-1+(L2-L1-1)*(X1/GO(0)))/L2:ZI=ZI+1
3270     X1=X1+CX+RI:Y1=Y1+CY
3280     FOR ZJ=1 TO ZC-1
3290       X2=PT(ZI)*NS:ZI=ZI+1
3300       Y2=PT(ZI)*NS*(L1-1+(L2-L1-1)*(X2/GO(0)))/L2:ZI=ZI+1
3310       X2=X2+CX+RI:Y2=Y2+CY
3320       EXEC DRAWL
3330       X1=X2:Y1=Y2:NEXT ZJ
3340     GOTO 3240
3350   NEXT SN
3360   EXEC MRESTORE
3370 ENDPROC

4000 REM Mandelbaum line
4010 REM - Input: Start and end diagonal corners in X1,Y1 and X2,Y2
4020 REM "Wrong attitude, you're not bringing that trash into my house."
4025 PROC MANDELBL
4030   NW=SZ(0):NH=SZ(1)+1
4040   XD=X2-X1:YD=Y2-Y1
4050   IF XD>0 AND YD<0 THEN A=0:WD=XD:HT=YD
4060   IF XD<0 AND YD<0 THEN A=1.5*PI:HT=XD:WD=YD
4070   IF XD<0 AND YD>0 THEN A=PI:WD=XD:HT=YD
4080   IF XD>0 AND YD>0 THEN A=0.5*PI:HT=XD:WD=YD
4090   WD=ABS(WD):HT=ABS(HT)
4100   NS=WD/NW:SH=INT(NH*NS)
4110   SG=INT((HT+SH-1)/SH):SH=HT/SG
4120   SX=GO(0)/NW:SY=SH/NH
4130   EXEC MSAVE
4140   AX=X1:AY=Y1:X=X1:Y=Y1:EXEC TRANSFORM:OX=X:OY=Y
4150   X=X2:Y=Y2:EXEC TRANSFORM:XD=X-OX:YD=Y-OY
4160   X=0:Y=0:EXEC TRANSFORM
4170   X=-X:Y=-Y:EXEC TRANSLATE:REM Translate
4180   EXEC ROTATE:REM Rotate
4190   X=SX:Y=SY
4200   IF (XD<0 AND YD<0) OR (XD>0 AND YD>0) THEN Y=SX:X=SY
4210   EXEC SCALE:REM Scale
4220   X=OX:Y=OY:EXEC TRANSLATE:REM Translate

4230   REM Walk through PT and draw
4240   FOR SN=0 TO SG-1
4250     ZI=0
4260     ZC=PT(ZI):ZI=ZI+1:IF ZC=0 THEN GOTO 4350
4270     X1=PT(ZI):ZI=ZI+1
4280     Y1=PT(ZI)*(SH-1)/SH-SN*(SH/SY):ZI=ZI+1
4290     FOR ZJ=1 TO ZC-1
4300       X2=PT(ZI):ZI=ZI+1
4310       Y2=PT(ZI)*(SH-1)/SH-SN*(SH/SY):ZI=ZI+1
4320       EXEC DRAWL
4330       X1=X2:Y1=Y2:NEXT ZJ
4340     GOTO 4260
4350   NEXT SN
4360   EXEC MRESTORE

4370   REM Return height to decide if it's time to stop
4380   X=AX:Y=AY+SH:EXEC TRANSFORM
4390   HT=SQR((X-OX)*(X-OX)+(Y-OY)*(Y-OY))
4400 ENDPROC

4500 REM === G
4505 PROC G
4510   CX=GX:CY=GY-GB:SA=0:EA=PI:EXEC MANDELB
4520   X1=GO(0):Y1=GY-GB:X2=0:Y2=GY+GB:EXEC MANDELBL
4530   CX=GX:CY=GY+GB:SA=PI:EA=0:EXEC MANDELB
4540   X1=GO(1):Y1=GY+GB:X2=GX:Y2=GY+GB-GO(0):EXEC MANDELBL
4550 ENDPROC

4600 REM === O
4605 PROC O
4610   CX=GX+OO:CY=GY-GB:SA=0:EA=PI:EXEC MANDELB
4620   X1=GO(0)+OO:Y1=GY-GB:X2=OO:Y2=GY+GB:EXEC MANDELBL
4630   CX=GX+OO:CY=GY+GB:SA=PI:EA=0:EXEC MANDELB
4640   X1=GO(1)-GO(0)+OO:Y1=GY+GB:X2=GO(1)+OO:Y2=GY-GB:EXEC MANDELBL
4650 ENDPROC

9000 REM "All aboard the pain train."
9010 DATA 39,16,15,3,-16,0,-16,0,-13,3,-13,3,-3,0,-3,0,0,10,0,10,-3,6,-3
9020 DATA 6,-13,10,-13,10,-16,6,-16,3,-16,11,16,-16,12,-16,12,-13,16,-13
9030 DATA 16,0,19,0,19,-13,23,-13,23,-16,19,-16,16,-16,5,25,-16,27,-16
9040 DATA 27,-13,25,-13,25,-16,19,36,-9,33,-10,32,-11,34,-13,36,-12,39
9050 DATA -12,34,-16,30,-14,29,-11,32,-7,35,-6,36,-5,34,-3,32,-4,29,-4
9060 DATA 34,0,38,-1,39,-5,36,-9,0
9070 DATA 53,16,15,23,-13,23,-16,20,-16,16,-16,13,-16,13,-13,16,-13,16
9080 DATA -3,13,-3,13,0,23,0,23,-3,20,-3,20,-13,23,-13,18,53,-13,53,-16
9090 DATA 46,-16,43,-16,43,-13,43,-10,43,-6,43,-3,43,0,53,0,53,-3,46,-3
9100 DATA 46,-6,51,-6,51,-10,46,-10,46,-13,53,-13,11,10,-16,7,-16,3,-16
9110 DATA 0,-16,0,-13,3,-13,3,0,7,0,7,-13,10,-13,10,-16,14,37,-16,33,-9
9120 DATA 29,-16,26,-16,26,0,29,0,29,-10,32,-4,34,-4,37,-10,37,0,40,0,40
9130 DATA -16,37,-16,0
9140 DATA 52,8,5,0,0,0,-8,3,-4,5,-8,5,0,3,10,0,8,-8,6,0,2,7,-4,9,-4,4,11
9150 DATA 0,11,-8,15,0,15,-8,6,18,-8,16,-8,16,0,18,0,20,-4,18,-8,2,23,-4
9160 DATA 21,-4,4,25,-8,21,-8,21,0,25,0,3,31,0,26,0,26,-8,12,32,-4,35,-4
9170 DATA 36,-5,36,-7,35,-8,32,-8,32,0,35,0,35,0,36,-1,36,-3,35,-4,3,41
9180 DATA 0,39,-8,37,0,2,38,-4,40,-4,6,42,-8,42,-1,44,0,45,0,47,-1,47,-8
9190 DATA 5,48,0,48,-8,50,-4,52,-8,52,0,0