Sierpinski carpet: Difference between revisions

=={{header|IS-BASIC}}==

<lang IS-BASIC>100 PROGRAM "Carpet.bas"

110 SET VIDEO MODE 5:SET VIDEO COLOR 0:SET VIDEO X 32:SET VIDEO Y 27

120 OPEN #101:"video:"

130 DISPLAY #101:AT 1 FROM 1 TO 27

140 CALL CARPET(30,0,1000,970,4)

150 DEF CARPET(X1,Y1,X2,Y2,LEV)

160 NUMERIC XT,XY,KX1,KX2,KY1,KY2

170 IF LEV>0 THEN

180 LET XT=(X2-X1)/3:LET YT=(Y2-Y1)/3

190 LET KX1=X1+XT:LET KY1=Y1+YT

200 LET KX2=X2-XT:LET KY2=Y2-YT

210 CALL CARPET(X1,Y1,KX1,KY1,LEV-1)

220 CALL CARPET(KX1,Y1,KX2,KY1,LEV-1)

230 CALL CARPET(KX2,Y1,X2,KY1,LEV-1)

240 CALL CARPET(KX2,KY1,X2,KY2,LEV-1)

250 CALL CARPET(KX2,KY2,X2,Y2,LEV-1)

260 CALL CARPET(KX1,KY2,KX2,Y2,LEV-1)

270 CALL CARPET(X1,KY2,KX1,Y2,LEV-1)

280 CALL CARPET(X1,KY1,KX1,KY2,LEV-1)

290 ELSE

300 PLOT X1,Y1;X2,Y1;X2,Y2;X1,Y2;X1,Y1

310 PLOT X1+4,Y1+4,PAINT

320 END IF

330 END DEF</lang>