Logic Masters Deutschland e.V.

Not all lab rats are cut out for the rigors of test mazes, but there's still a lot we can learn from their daily habits...

Punky the rat starts in the upper-left corner and follows a path to his bed in the lower-right corner, moving orthogonally and/or diagonally between adjacent cells. The path does not intersect itself or return to any previously visited cell, and cannot cross the tunnel walls (or diagonally across the walls' endpoints).

Punky is hungry! His path must cross over every redcurrant in the grid. Digits on either side of a redcurrant have opposite parity (i.e. one is odd and one is even).

Punky is nonconformist! Adjacent digits along the path must not satisfy any of the XV, Kropki, or German Whispers constraints: they must not sum to five or ten, must not be consecutive or in a 1:2 ratio, and must not have a difference of 5 or greater.

Punky's enclosure is full of enrichment! Some cages show their sums; Punky visits at most one cell in each cage. The purple exercise wheel holds a set of consecutive, non-repeating digits in no particular order. The three digits on the orange exercise-wheel stand must each be from different entropic classes (the classes are 1/2/3, 4/5/6, and 7/8/9). The grey squares indicate even digits and the grey circle indicates an odd digit, and normal sudoku rules apply.

Thanks to Marty Sears, creator of the "Rat Run" series, for inspiring this puzzle!

Online solver: SudokuPad