I have a joke for anons (eurofag tries to translate - don't hate me)
2 mathematicians, 2 physicists and 2 engineers are seperately being locked in a lab with 2 spheres for each pair of scientists.
After on week they open the mathematicians' lab:
They succeeded in placing one sphere perfectly upon the other.
Then they open the physicists lab:
One sphere is hovering in the middle of the room and the other sphere revolves the first one perfectly.
Then they open the room with the engineers:
One sphere is missing.
And the other one is broken.