Pipe It by ANDREY NOVIKOV FREE

  

Pipe It comes from Andrey Novikov and Alexey Pajitnov, who is the author of the classic arcade game Tetris. The object is to place the pipe pieces in the grid so that every node gets lit. Also, all the pieces must be utilized.

  

There's a lot to like about Pipe It. First, when all the pieces are place the entire grid is not used. The graphics are good. I particularly like the levels that make you think there will be a symmetric diagram. Deceptive!

What could be better? Once you're stuck, it's impossible to see the outline of the individual pieces. So in effect, you have to move them all off the board.

There are 600 levels - way too many.  Also, in order to do the Normal levels, you have to first complete most of the 150 Easy levels.

There is something very relaxing about this puzzle. I did complete all the easy levels and moved on to the normal, hard and challenging levels.   At the moment I've solved 60 of the 150 challenging levels.
https://itunes.apple.com/us/app/pipe-it/id1198940085?mt=8