Basic game play:
By tapping the individual tiles you can rotate them. Rotate them until there is no open end left. If you solve the level it will become inverse white loops on black background.
If you solve the level it will remain solved until you either restart the application, hit the shake button, which will rotate all tiles randomly, or you randomize all levels by hitting reset. To allow as much freedom in gameplay as possible you can jump to any level by simply clicking > to advance.
There are eight different sizes for levels and each size has three different random layouts. So in total you have 24 levels. But each level is randomly generated leaving you with an infinite number of puzzles.
In edit mode you can clear the level, generate a single level with the rand button, or draw your own, just slide and create connections.
Source: The Developer Website.