100 SCREEN 2
110 CLS
120 x1 = 256 : y1 = 192
130 i1 = -1 : i2 = 1
140 r1 = -2 : r2 = 1
150 s1 = (r2-r1)/x1 : s2 = (i2-i1)/y1
160 FOR y = 0 TO y1
170   i3 = i1+s2*y
180   FOR x = 0 TO x1
190     r3 = r1+s1*x
200     z1 = r3 : z2 = i3
210     FOR n = 0 TO 30
220       a = z1*z1 : b = z2*z2
230       IF a+b > 4 GOTO 270
240       z2 = 2*z1*z2+i3
250       z1 = a-b+r3
260     NEXT n
270   PSET (x,y),n-16*INT(n/16)
280   NEXT x
290 NEXT y
300 GOTO 300