Client for playing 300 publicly available Sokoban puzzles on a computer or phone.
on_slider = function(slider, x,y)
	if x < slider.x0-slider.w/2 or x > slider.x1+slider.w/2 then return end
	if y < slider.y0-slider.h/2 or y > slider.y0+slider.h/2 then return end
	return true
end