Obitaru (from Japanese, literally "orbital") is a logic puzzle published by Nikoli. A grid contains white and black circles; black circles may contain numbers. The goal is to draw square or rectangular loops ("belts"). The loops may cross each other, but parallel lines cannot pass through the same cell. Loops must pass through all white cells. There may be loops that do not pass through any white circle. A black circle should be inside exactly one loop (there can be no more than one black circle inside the loop). If the black circle contains a number, it will be equal to the number of white circles through which the loop passes around this black circle.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.