Client for playing 300 publicly available Sokoban puzzles on a computer or phone.
on_area = function(s, x,y)
	if s.x == nil then return end
	if x < s.x then return end
	if x > s.x+s.w then return end
	if y < s.y then return end
	if y > s.y+s.h then return end
	return true
end