Masyu

Masyu is a seriously challenging Japanese logic puzzle which will put experienced puzzlers and would-be puzzlers to the ultimate test. Unlike many puzzles Masyu has no numbers or letters. It is played on a grid of squares, some of which contain white or black circles. The objective is to draw a continuous loop that passes through each of the circles. Sounds easy? It's not - the loop must be a continuous path that follows a host of strict rules making your task perplexing! Challenging yet extremely addictive, this is the type of puzzle you just can't put down.