Draw a Koch curve. See details: Koch curve

100 PROGRAM "Koch.bas"
110 OPTION ANGLE DEGREES
120 SET 22,1:SET 23,0:SET 24,42:SET 25,26
130 OPEN #101:"video:"
140 DISPLAY #101:AT 1 FROM 1 TO 26
150 SET PALETTE 0,252
160 PLOT 300,700;ANGLE 0;
170 FOR I=1 TO 3
180   CALL KOCH(0,800)
190   PLOT RIGHT 120;
200 NEXT 
210 DEF KOCH(A,D)
220   IF D>12 THEN
230     LET D=D/3
240     CALL KOCH(A,D)
250     CALL KOCH(60,D)
260     CALL KOCH(-120,D)
270     CALL KOCH(60,D)
280   ELSE 
290     PLOT LEFT A;FORWARD D;
300   END IF 
310 END DEF