Hashi Bridge is a free puzzle app game https://itunes.apple.com/us/app/hashi-bridge/id792603343?mt=8.
The object is to connect the numbered circles to other circles. A 4 means that there will be 4 bridges to other circles. Two circles may have 2 bridges between them, no more.
There are 130 levels. I've done so many Hashi puzzles...they're good, but I don't feel the addiction.