Colorful sponge cake, in and out of cages. Mostly out.
ALL possible Battenberg symbols are given.
Rules:
Normal Sudoku rules apply.
Digits within cages sum to the small number in the top left corner of that cage.
Battenberg squares mark all 2x2 areas in which odd and even digits form a checkerboard pattern. No 2x2 area without a Battenberg square contains alternating odd and even digits.
Estimated difficulty: 1.5 out of 5
Solve on SudokuPad