Herringbone (Double Helix) Gear and Base

Do you like gears? You'll like this one twice as much, since it's a double helical gear, also known as a herringbone gear. Print two of them, and flip one over. You'll notice that they mesh perfectly, and have the side benefit of self-aligning; there's no thrust produced by these gears. You can print the attached base if you want to make a toy of sorts out of it.