define max = 15, w = 640, h = 480
define py = 0, px = 0, sx = 0, sy = 0
define xx = 0, xy = 0

bgcolor 0, 0, 0
cls graphics
fill on

do

	let px = 0

	do

		let sy = (py - h / 2) / 150
		let sx = (px - w / 2) / 150

		let i = 0
		let x = 0
		let y = 0

		let xy = x * x + y * y

		do

			let xx = x * x - y * y + sx + .1
			let y = 2 * x * y + sy
			let x = xx

			let i = i + 1

		loop i < max and xy < 4

		wait

		fgcolor 220 + i * x, 220 + i * y, 230 + i * xy
		rect px, py, 4, 4

		let px = px + 4

	loop px < w

	let py = py + 4

loop py < h