This is a three-dimensional masyu puzzle. The six squares depict the layers of a $6\times6\times6$ cube. The goal is to make a single loop in 3D space which fulfills the following properties:
- The line passes through centres of cells and makes 90-degree turns only.
- The line cannot cross itself or branch off in multiple directions.
- The line passes through every white and black circle.
- When passing through a white circle, the line must go straight through the circled cell and make a turn directly before or after that cell (or both).
- When passing through a black circle, the line must make a turn in the circled cell and continue straight for at least one cell on both sides.
- Red squares are lava. No line passes through lava.
Note: Feel free to use any notation you feel the most comfortable with, as long as it's properly explained. My way is to use diagonal lines to show movement between layers.