LOOP is an elegant puzzle game based on paths through a hex grid. You start with a scrambled grid, swap pairs of hexes and when you finish all the loops link up in perfect harmony (see image).
No tutorial, but 100 individual puzzles introduce the key mechanic and the two special devices. Clicking on a hex highlights its border; clicking on another then gracefully swaps them over. One device is a simple arc inside a circle, which is fixed in location but changes colour when clicked. The other has three arcs inside a circle of arrows and is also fixed in location but rotates when clicked.
The maximum size of grid is a hexagon with four hexes to a side, sometimes a bit moth-eaten (see picture). The earlier puzzles often have a smaller grid, and some have holes in them. There are puzzles wth paths of just one colour, while others may use six or more. Sometimes the paths are tightly packed, using all sides of the hexes, sometimes they are quite sparse.
Finally there is a puzzle generator. The puzzles are less varied than the individual levels, but the supply appears unlimited. It’s a lovely puzzle with hours of enjoyment, and I highly recommend it to any puzzle aficionado. You can get it on Steam or direct from http://loopthegame.com/.
But of course the question I want to address here is: how does that generator work? And could it be even better? We might have to build a clone to do that.