Cushion: Double Shuffle
Unless you are a mathematician, you may not be interested in the special properties of Double Shuffle.
On the striped side, the lighter part has exactly the same area as the darker part; on the other side the colours have been shuffled about to make solid blocks but light and dark still have exactly the same area.
Buy using the link at the top of this page
or as one of twelve cushions, in 12 Pillows of Wisdom.