This can be knit or crochet. I chose crochet because it is quicker.

A ‘perfect shuffle’ is what happens when you take the two halves of a pack of cards and shuffle them so that the cards alternate. The ‘pack’ in this case is just ten cards. The first column shows the colours at the start; the second column shows their positions after the first perfect shuffle; the next column shows the result of another shuffle. Eventually, you get back to where you started. In this example that takes ten shuffles.

At first glance the colours look random but, on closer inspection, they create an interesting pattern.