How to play
Draw one closed loop along the grid lines. Every number says how
many of its four sides the loop uses.
- A 3 has the loop along three of its four sides. A
0 has the loop nowhere near it. Empty cells say nothing —
the loop may do as it likes around them.
- There is exactly one loop. It never crosses itself, never
branches, and never leaves a loose end. Every corner it reaches, it must
also leave.
- Tap an edge to draw it. Drag along several to draw a run. Use
Rule out to mark an edge the loop cannot use — those
crosses are how you make progress.
- Tap an edge again to clear it. On a desktop, right-click
rules an edge out without switching modes.
- A number dims once it has the right count of lines, and turns
red if too many are drawn. A corner where
three lines meet is flagged as well — the loop can never fork.
- Every puzzle can be reasoned out from the clues alone — you never need
to guess.
Where to start
- Rule out all four sides of every 0. That is free, and it
gives its neighbours something to work with.
- A 3 next to a 0 is forced: the three
sides away from the 0 must all be drawn.
- Two 3s side by side always have the edge between them
drawn, plus the two outer edges opposite it.
- Watch the corners. If a corner already has one line and only one other way
to go, the loop has to take it.
- Stuck? Hint finds the next edge logic settles, and says
which clue proves it.