def set(x, y, r, g, b)
			check_coords(x, y)
			self[x, y] = Color.new(r, g, b)
		end
def set(x, y, r, g, b)
			check_coords(x, y)
			self[x, y] = Color.new(r, g, b)
		end
Set given pixel identified by +x+, +y+ to +r+, +g+, +b+

 See <tt>[]=</tt> for a method that takes +Color+ instance instead
 of individual components.

 You still have to call +show+ to make the changes visible.