sum-grid.love/0040-check_status

check_status = function()
	for y=1,2 do
		for x=1,2 do
			if Problem.data[y][x] == '' then
				return ''
			elseif Problem.data[y][x] ~= Solution.data[y][x] then
				return 'no'
			end
		end
	end
	return 'yes'
end