What not to observe – The higher the speed, the more stroboscopic artifacts occur due to the interaction of your monitor’s frame rate and the frame-wise display of the rotating wheel (think of the backwards rotating spike wheels in Western movies).

What to observe – When a fairly high speed (more precisely: local temporal flicker frequency) is reached, the arcs take on weak (desaturated) colours, for instance I see a red-brown in the centre three arcs. When reversing the direction of rotation, the colours flip places.