REM ***** MAD TEDDY'S MANDELBROT SET SERIES: REGION #25 *****

REM x limits: .2505, .2838333
REM y limits: -.0125, .0125

SCREEN 12

iterationlimit = 100

ylow = -.0125
yhigh = .0125
xlow = .2505
xhigh = xlow + (yhigh - ylow) * 4 / 3

FOR i = 0 TO 479
    FOR j = 0 TO 639
        x = xlow + j * (xhigh - xlow) / 639
        y = ylow + i * (yhigh - ylow) / 479
        xc = x: yc = y
        iterations = 0
        rsquared = 0
        DO UNTIL rsquared >= 4 OR iterations > iterationlimit
            u = x * x - y * y + xc
            v = 2 * x * y + yc
            rsquared = u * u + v * v
            x = u: y = v
            iterations = iterations + 1
        LOOP
        IF rsquared >= 4 THEN
            IF iterations > 100 THEN
                colour = 0
            ELSE
                colour = 1 + (iterations + 0) MOD 15
                REM ran 15 times, adding 0, 1, 2,... 14,
                REM for different frames of the animation
            END IF
        ELSE
            colour = 0
        END IF
        PSET (j, i), colour
    NEXT j
NEXT i

a$ = ""
DO: a$ = INKEY$: LOOP UNTIL a$ = CHR$(27)