Tangram XL
Simple version of the popular Tangram puzzles designed with kids in mind. It is designed to avoid unnecessary decoration to keep kids’ attention on geometric concepts.

Finger Physics (web and Android)
Fit together different and moving shapes to solve puzzles. The free version features around 100 levels with various objectives and difficulty levels.

Flow Free
Connect matching colors with pipe to create a flow. Pair all colors, and cover the entire board to solve each puzzle. But watch out, pipes will break if they cross or overlap.

Genius Brain
Using clues, players must identify in which column a given icon is located on a large board in this version of Einstein’s puzzle. It is aimed at improving your visual memory, ordering your thinking, helping form cause-effect relations, and more.

Monorail
Draw lines to connect “stations” and create a working monorail system in this game that challenges visual/spacial/geometric skills. According to the developers, Kindergartners can solve the beginner levels. Mathematicians from MIT have struggled to solve the most difficult ones.