This is an interesting puzzle game!
The rule is very simple.
Find the route that visits each vertex exactly once and finally go back to the starting vertex.
Levels is from easy to difficult in the design. In order to attract more people to know this game, the previous level design is very simple. However, subsequent levels will gradually increase the difficulty.
Each player will eventually stuck at a level not to move forward. But when you solved the stuck level, you will become more intelligent.
1.add "test intelligence"
2.add "view intelligence ranking"