'Mandelbrot Set Generation Program
'By Louis Nemzer


CLS

RA = .001
RB = .001
I = 1000

SCREEN 12
WINDOW (-1.8, 1.25)-(.5, -1.25)
CLS

FOR A = -1.8 TO .5 STEP RA
FOR B = 0 TO 1.25 STEP RB
GOSUB TEST
NEXT B
NEXT A
END

TEST:
 LET Q = 0
 LET M = A
 LET N = B

 FOR Z = 1 TO I

 LET J = (M * M) - (N * N)
 LET K = (2 * M * N)

 LET M = J
 LET N = K

 LET M = A + M
 LET N = B + N

 IF M >= 2 THEN GOTO 20
 IF M <= -2 THEN GOTO 20
 IF N >= 2 THEN GOTO 20
 IF N <= -2 THEN GOTO 20

 NEXT Z
RETURN
20

IF Z < 5 THEN
LINE (A, B)-(A, B), 8
LINE (A, -B)-(A, -B), 8
GOTO 30
END IF

IF Z >= 5 AND Z < 10 THEN
LINE (A, B)-(A, B), 15
LINE (A, -B)-(A, -B), 15
GOTO 30
END IF

IF Z >= 10 AND Z < 20 THEN
LINE (A, B)-(A, B), 3
LINE (A, -B)-(A, -B), 3
GOTO 30
END IF

IF Z >= 20 AND Z < 30 THEN
LINE (A, B)-(A, B), 12
LINE (A, -B)-(A, -B), 12
GOTO 30
END IF

IF Z >= 30 AND Z < 50 THEN
LINE (A, B)-(A, B), 5
LINE (A, -B)-(A, -B), 5
GOTO 30
END IF

IF Z >= 50 AND Z < 100 THEN
LINE (A, B)-(A, B), 6
LINE (A, -B)-(A, -B), 6
GOTO 30
END IF

IF Z >= 100 AND Z < 500 THEN
LINE (A, B)-(A, B), 9
LINE (A, -B)-(A, -B), 9
GOTO 30
END IF

IF Z >= 500 AND Z < I THEN
LINE (A, B)-(A, B), 4
LINE (A, -B)-(A, -B), 4
GOTO 30
END IF

30 RETURN