Colorful Clock

Colorful Clock is listed here under Puzzle. There is no launcher and no install between you and it. It is built for touch, so a phone or a tablet is the natural place for it. Catalogued as fun, html5, kids, mobile, puzzle.

It is drawn for a tall screen, so it fills a phone held upright rather than a wide monitor. Everything runs client-side, so there is nothing to set up before you start.