Filo is the kind of puzzle you can explain in ten seconds and still be thinking
about an hour later.

The grid holds pairs of coloured nodes. Drag a thread from one node to its twin,
moving only horizontally and vertically, never crossing another thread.

There is one more rule, and it changes everything: each node has a number
printed on it, and the thread must cover EXACTLY that many cells. Not one more,
not one fewer. And when you are done, not a single cell of the grid may be left
uncovered - except obstacles, which no thread can ever cross.

The hardest levels add a portal too: two cells far apart on the grid that count
as neighbours, letting a thread jump from one side of the board to the other in
a single step.

This is not a game of luck, and not a game of speed. Every level has exactly one
solution, verified one by one before it ever reached the app: if you find it,
it's because you worked it out.

• 1000 levels, from 5×5 grids with three threads to 9×9 with eight
• Obstacles and a portal in the hardest levels, so difficulty isn't just about
how big the grid is
• A new puzzle every day, free forever, with your own timer
• A live counter as you draw, so you always know where you stand
• Unlimited undo, and reset whenever you like
• No timers, no lives, no pressure
• Colours chosen to stay distinct for red-green colour blindness, with a number
on every node so nothing rests on colour alone
• Light and dark themes
• Plays completely offline

The first 200 levels and the daily puzzle are free, forever. The other 800 open
with a single payment, which also removes ads: the free version shows one ad
every two levels, nothing more.

No subscription. No account. The only thing that leaves your device is what's
needed to show an ad, and only before you unlock.