For this challenge you will have to model a corner contraption. No restriction here, but it might be a good idea to make all inside dimensions larger than 60mm.

You task is to fill this corner with a pyramid shaped object as demonstrated.
The triangle looking pyramid base is the only visible part of this pyramid.
Corners of the pyramid base should be distant from the contraption corner 40, 50 and 60mm far. The order is not important.