What is the Electric Tangram game, how does it work?

According to the introduction of Roman Langrehr, Electric Tangram is a Puzzle game on the Android platform. There is currently a 1.4.0.1 version released on May 29, 2013, you can see the details below.

Electric Tangram is a Brain & Puzzle-Game, where you have to finish an electric circuit. The goal is to make the light bulb glow and fill all the gaps (like in Classic Tangram). (But you don't need to connect all tiles!)

Control:
Move a tile from the lower part of the screen in the playing field. Tap it shortly to rotate it. A tile always rotates clockwise about the touched point. To remove a tile again, leave your finger a few seconds on it.
Once a tile is in the playing field, you can't move it anymore (only rotate and remove), so try to place all pieces in a smart order and at a smart position.
Avoid short-circuits.

At the moment, there are 55 levels). To unlock a level, solve the one before.