Inside And Outside The Loop

A clever twist on Loop-the-Loop (Slitherlink) from a brilliant Japanese compiler has produced a remarkable puzzle that appears similar, but requires a completely different method of solving.

Here, instead of focusing on the progression of the line, the solver must consider the spaces in the grid and whether they lie inside or outside of the loop.

Those who are familiar with Loop-the-Loop should be able to adapt to this extraordinary variant, but success is not guaranteed. The approach to solving is quite different. We have known enthusiasts of Loop-the-Loop who found this puzzle very tricky, at first, while others took to it without hesitation.


Connect adjacent points (•) so that a single loop is formed with no crossings or branches. The line must go through every point in the grid and can only move horizontally or vertically along the dotted lines. A letter in a cell indicates whether the cell lies inside (I) or outside (O) the loop.

Related Puzzles

Loop-The-Loop Loopy