Irupu ("I-Loop") is a logic puzzle invented by Naoki Inaba (Japan). A rectangular or square grid contains circles in some cells. The goal is to locate some blocks in the grid, having the size either 1 x 3 or 3 x 1. Each block contains one circle and must be orthogonally adjacent to exactly two other blocks. All block cells form one contiguous region.
| Author: Ted Warner |
| Publisher: Independently published |
| Publication Date: May 11, 2018 |
| Number of Pages: 115 pages |
| Language: English |
| Binding: Paperback |
| ISBN-10: 1981074945 |
| ISBN-13: 9781981074945 |