Logic Masters Deutschland e.V.

Rules

Draw two non-branching, non-self-crossing loops that move orthogonally through the centers of some cells. Every cell not containing a black circle must be visited by exactly one of the two loops. Cells with a black circle are visited by either no or both loops. If visited by both, the two loops must cross, but not turn at their intersection or otherwise overlap. Neither loop may pass through solid cell borders, if given.

I recommend drawing the loops in contrasting colors while solving. If you want the answer check to trigger, you will need to trace over all lines in green.

Here is a small example to illustrate the rules. You can try solving the example online here (no answer check).

Penpa+ Link