They are made from sweet chestnut (it needs to be something dense otherwise the point gets squished the first time it spins off a table onto a hard floor). I deliberately experimented with different shapes and patterns. All of them work OK but some are harder to get spinning than others. After a bit of practice it is possible to get all five spinning at the same time. The colours are simply cheap wax crayon, mostly applied with the lathe spinning.
A few weeks later I made another, slightly bigger one from a piece of oak:
This one spun more stably and for longer than the first batch, probably because it's slightly heavier (sorry the photo is so blurry; I couldn't keep it in focus as it danced randomly around the table).