First click anywhere on the center board. A random pattern of curved loops will appear.

Try to make it one big loop by swapping some of the double bends and crosses. To achieve this, first click a source-square of the board, then the target-square for your swap.
Note that the border pieces cannot be part of the swap.
The less moves you need to accomplish your task the better.

Click on one of the border pieces (bends at top, bottom, left or right) to check whether all loops are connected. The loop will turn red.

You win when all bends are part of one big loop, otherwise you lose.

In variant 2 the cross intersections cannot be changed.
The other variants have a bigger board and/or more bends.

Variants 8 to 16: Here you are given the minimum amount of double bends possible to make a loop.
Experts: Try to use the smallest number of moves to make such a loop.

Good luck!

 
Background design: Fractal Mo99121j by Morgan Owens and Karl Scherer.

For more freeware as well as real puzzles and games see my home page http://karl.kiwi.gen.nz.