Normal sudoku rules apply. Finkz the rat must reach the cupcake by finding a path through the maze. The path will be a snaking line that passes through the centres of cells, without visiting any cell more than once, crossing itself or passing 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 through a rounded corner / end of a wall. Finkz may only pass directly through a purple arrow if moving in the direction the arrow is pointing. An arrow always points to the smaller of the two values it sits between. Cells connected by a blackcurrant are in a 1:2 ratio (one is double the other.) Not all possible blackcurrants have been given. In this experiment, the correct path will be a valid alternating parity line - ie: any pair of adjacent cells along the path must contain one even digit and one odd digit.