Super Looper: free puzzle app game for iphone, ipad

Super Looper is a puzzle app game that incorporates Celtic Knots. Who doesn't like Celtic Knots? They're fun & beautiful.  The object of Super Looper is to swap tiles to make the shape shown on the right.

There are 100 handcrafted levels. I've done only 6. I'm not feeling any addiction.
https://itunes.apple.com/us/app/super-looper-puzzle-game/id921061059?ls=1&mt=8