local function move(map, startX, startY, dX, dY)
	local targetX, targetY = startX + dX, startY + dY
	if not map[targetX][targetY] then return startX, startY; end
	if map[targetX][targetY].isBox then
		local slideX, slideY = targetX + dX, targetY + dY
		if not (map[slideX] and map[slideX][slideY] and map[slideX][slideY].isWalkable) then return startX, startY; end
		local empty, boxTile = map[slideX][slideY], map[targetX][targetY]
		local sprite = boxTile.box
		sprite.x, sprite.y = empty.x, empty.y
		empty.box = boxTile.box
		empty.isBox = true
		empty.isWalkable = false
		boxTile.box = nil
		boxTile.isWalkable = true
		boxTile.isBox = false
	end
	if map[targetX][targetY].isWalkable then
		local target, origin = map[targetX][targetY], map[startX][startY]
		hero.x, hero.y = target.x, target.y
		target.isHero = true
		target.isWalkable = false
		origin.isHero = false
		origin.isWalkable = true
		return targetX, targetY
	end
	return startX, startY
end