Parallel running tracks double the running period of a marble or allow competition between 2 marbles: Does one of the marbles run faster than the other one or do they run synchronically? Lane changing elements and new coincidental elements make it possible to cross over from the conventional lane into double lanes.
The Duo-Set contains 24 cubes made of natural beech wood with 17 different functions, 3 marbles.
Use spaces to separate tags. Use single quotes (') for phrases.