Filter Jam is a free sliding block puzzle in the style of classic traffic-jam puzzles, with 40 levels that start easy and end very hard. Every level was checked by a computer solver, so par is the true minimum. It works on phones, tablets and computers with no download and no sign-up, and your progress is saved in your browser.
It's made by Ned Games and inspired by real delivery days at Ned Air Filters in San Antonio, where a van full of AC filters really can get jammed.