Masyu is a puzzle game where the object is to create a single, continuous, non-intersecting loop that passes through all the special spaces. A line can enter and exit a grid cell in one of the four cardinal directions. You play only with your mouse. To add lines, simply hold the LEFT mouse button down and drag from one grid cell to another. To remove, use the MIDDLE mouse button.
There are two types of special spaces:
A white space must be traveled straight through, but must turn in the previous and/or the next cell in its path.
A black space must have a turn on their grid cell, but both the next and previous cells must have been traveled straight through.