fastgraphics

graphsize 384,384
refresh
kt = 319 : m = 4.0
xmin = -2.1 : xmax = 0.6 : ymin = -1.35 : ymax = 1.35
dx = (xmax - xmin) / graphwidth : dy = (ymax - ymin) / graphheight

for x = 0 to graphwidth
	jx = xmin + x * dx
	for y = 0 to graphheight
		jy = ymin + y * dy
		k = 0 : wx = 0.0 : wy = 0.0
		do
			tx = wx * wx - wy * wy + jx
			ty = 2.0 * wx * wy + jy
			wx = tx
			wy = ty
			r = wx * wx + wy * wy
			k = k + 1
		until r > m or k > kt
		
		if k > kt then
			color black
		else
			if k < 16 then color k * 8, k * 8, 128 + k * 4
			if k >= 16 and k < 64 then color 128 + k - 16, 128 + k - 16, 192 + k - 16
			if k >= 64 then color kt - k, 128 + (kt - k) / 2, kt - k
		end if
		plot x, y
	next y
	refresh
next x
imgsave "Mandelbrot_BASIC-256.png", "PNG"