- arithmetic equalities, and
- wall constraints
the 15-puzzle got upgraded to "i am smaart", a game for the brain.
Besides, you will not miss the classic features like number sequences (in decimal, hex and Roman notation) or letter sequences (in 3 alphabets: Latin, Greek and Cyrillic).
And you will also have dynamically generated images which will never repeat: with circles, with triangles or with rectangles, filled or outlined.
All in 3x3, 4x3, 6x2, 5x3, 4x4, 6x3, 5x4, 6x4, 6x5, 6x6, 7x6 and 8x6 boards.
Happy unpuzzling, everyone! :)
The game uses a variable display refresh rate: from maximum when needed to zero, in order to save battery power. It preserves the experience and extends the autonomy.