The object is to remove all the scales in groups. Only scales that are not overlapped by any others can be removed. It's a bit like Mahjongg (sometimes called Shanghai) - as in that game, you can't see everything because some scales are hidden beneath others.
In the image, two hexagonal scales are being removed - they leave a trail of sparks as they fly towards their box on the right.
You can choose animated textures similar to the diagram, or fabric tiles. Other features include all the usuals - different skill levels, graphics auto-size to match window, position saved automatically when you quit, background music...
There's no time limit on the free trial (shareware) version, but the puzzles will repeat after ten at each skill level. The full version can create infinitely many puzzles, and also allows you to define your own layouts.