Normal sudoku rules apply. AIM OF EXPERIMENT: Finkz the rat must reach the cupcake by finding a path through the maze. The path must not visit any cell more than once, cross itself, or pass through any thick maze walls. As well as moving orthogonally, Finkz may move diagonally if there's a 2x2 space in which to do so, but may never pass diagonally through a round wall-spot on the corner of a cell. NULLIFIERS: In each row, column and 3x3 box there is one 'nullifier' cell to be located. The value of a nullifier cell is zero. Each nullifier cell contains a different digit. MOTION SENSORS: The value on a pink motion sensor indicates how many of the (up to 9) cells immediately surrounding the sensor are visited by Finkz. The sensor itself is counted, if visited. BLACKCURRANTS: Values connected by a blackcurrant have a 1:2 ratio. GRAPES: Values connected by a green grape have a difference of at least 5. FORBIDDEN DOORS: Values connected by a red X sum to 10. Finkz may not pass directly through a red X. TEST CONSTRAINT: In this experiment, if a row / column / box is visited by Finkz, then the values of ALL the visited cells in that row / column / box must sum to exactly 13 (even if the cells aren't all adjacent on the path.)