Moon or Sun is a puzzle type originally found in Puzzle Communication Nikoli volume 154. Here is a six-puzzle exploration of this type.
1. Create a single loop that passes through some cells without branching, intersecting, or moving diagonally.
2. Each bold-outlined region can be entered and exited only once.
3. Bold outlined regions contain moons or suns. In each region, the path must either pass through all of the moons and pass through none of the suns or pass through all of the suns and pass through none of the moons.
4. The path must pass through at least one symbol in each bold-outlined region.
5. The regions the path passes through must alternate between suns and moons.
All of the puzzles can be found organized in this printable PDF, or in the images below.
PDF Moon or Sun
This puzzle, has been corrected…again.