epidemian/index.html

## index.html
<!DOCTYPE html>
<body>
<script src="//cdnjs.cloudflare.com/ajax/libs/coffee-script/1.7.1/coffee-script.min.js"></script>
<script src="owl.coffee" type="text/coffeescript"></script>

## owl.coffee
canvas = document.createElement 'canvas'
canvas.style.backgroundColor = '#240202'
canvas.style.transform = 'scale(0.5) translate(-480px,-570px)'
W = canvas.width = 960
H = canvas.height = 1140
D = 50
R = D / 2
ctx = canvas.getContext '2d'
imageData = ctx.getImageData 0, 0, W, H
data = imageData.data
owl = '''

\ * * * * * * * * *
\  *     * *     *
\ *   *   *   *   *
\    * *     * *
\ *   *       *   *
\  *     * *     *
\ * *     *     * *
\  * *         *
\ * * * * * * *   *
\  * * * *
\ * * * * *       *
\  * * * *
\   * * * *       *
\    * * * *
\     * * * *     *
\      * * * *
\       * * * *   *
\        *   * *
\       *   *   * *
\  * * * * * *   *
\                 *
'''.split '\n'

insideDot = (x, y) ->
  w = 0
  for du in [-1..1] then for dv in [-1..1]
    u = x // D + du
    v = y // D + dv
    continue unless owl[v]?[u] is '*'
    dx = x - (u * D + R)
    dy = y - (v * D + R)
    d = dx * dx + dy * dy
    w += 1 / (d * d)
    return yes if w > 0.0000008
  no

for y in [0...H] then for x in [0...W] when insideDot x, y
  i = (y * W + x) * 4
  data[i] = data[i+1] = data[i+3] = 255
  data[i+2] = 214

ctx.putImageData imageData, 0, 0
document.body.appendChild canvas
	<!DOCTYPE html>
	<body>
	<script src="//cdnjs.cloudflare.com/ajax/libs/coffee-script/1.7.1/coffee-script.min.js"></script>
	<script src="owl.coffee" type="text/coffeescript"></script>
	canvas = document.createElement 'canvas'
	canvas.style.backgroundColor = '#240202'
	canvas.style.transform = 'scale(0.5) translate(-480px,-570px)'
	W = canvas.width = 960
	H = canvas.height = 1140
	D = 50
	R = D / 2
	ctx = canvas.getContext '2d'
	imageData = ctx.getImageData 0, 0, W, H
	data = imageData.data
	owl = '''

	\ * * * * * * * * *
	\ * * * *
	\ * * * * *
	\ * * * *
	\ * * * *
	\ * * * *
	\ * * * * *
	\ * * *
	\ * * * * * * * *
	\ * * * *
	\ * * * * * *
	\ * * * *
	\ * * * * *
	\ * * * *
	\ * * * * *
	\ * * * *
	\ * * * * *
	\ * * *
	\ * * * *
	\ * * * * * * *
	\ *
	'''.split '\n'

	insideDot = (x, y) ->
	w = 0
	for du in [-1..1] then for dv in [-1..1]
	u = x // D + du
	v = y // D + dv
	continue unless owl[v]?[u] is '*'
	dx = x - (u * D + R)
	dy = y - (v * D + R)
	d = dx * dx + dy * dy
	w += 1 / (d * d)
	return yes if w > 0.0000008
	no

	for y in [0...H] then for x in [0...W] when insideDot x, y
	i = (y * W + x) * 4
	data[i] = data[i+1] = data[i+3] = 255
	data[i+2] = 214

	ctx.putImageData imageData, 0, 0
	document.body.appendChild canvas