LooM

one thread, closed on itself

every puzzle is checked by solver before you see it.
it has exactly one solution, and pure logic always
reaches it. you will never have to guess.

size

difficulty

← arcade

0/0 0:00

Draw a single closed loop. Each number says how many of its four sides the loop uses.

the loop closes

0:00

How it works

Draw one single closed loop along the grid lines. The loop never branches and never crosses itself.

A number tells you exactly how many of that cell's four sides the loop uses. Cells without a number can have any amount.

Controls

Click or drag an edge to draw thread. Drag along to draw fast.
Right-click, or hold Shift, or the ✕ button — mark an edge as definitely empty. Optional, but it's how you keep track of what you've ruled out.
Z undo · Y redo · H hint

The one promise

Every puzzle here was solved by a machine before it reached you, using only deduction rules — never trial and error. If you're stuck, there is a forced move somewhere. Guessing is never required, and never necessary.

Techniques

Named deduction patterns. The hint button uses these, and it tells you which one applies. Nothing here is required reading — you'll rediscover most of them on your own, which is the better way.

Paused

The clock is stopped.

Revealing costs you the puzzle — it won't be recorded or timed. It's there so you can always see that the loop really was findable.