1)Classic one
2)Transparent-skeleton
3)Pen holder (can ruin your desk, but fun!)
4)Overcomplicated (testing)
Cats really love this thing... actually everybody:)))
Every spin top can be printed without support if you have enough cooling. 3 wall recomended, 0.16 layer, 20-30% infill recommended.
"5mm" in file name mean that it can be printed with socket for ball bearing, it give better spin.
The author hasn't provided the model origin yet.