Screen interview first, then a more in-depth interview to test your depth. The screening was basic mechanical questions like what material is more stiff, brain teasers, etc. Next was more in-depth, where you talk with the actual person you're working with. He asks you some more advanced mechanical questions.

You have two plates sitting on top of each other. On both plates, there is a hole where a thru-bolt connects them.

On the top plate, there is a slot, and on the bottom plate, there is a hole directly under it. What purpose does this serve?