Any amount of rotation will not change the angle between the two spokes. This is because each piece of the wheel moves in unison as the rotation is applied. Nothing changes about the wheel. Imagine instead of rotating the wheel, we instead rotated the camera that is capturing the wheel (or the person looking at the wheel rotates their head). This is a good way to see how the wheel itself isn't changing at all, but instead rather just the look of it is changing.