How to do two sphere are cut from a certain uniform rock?

This does not sound like a school problem, nor mathematics.
However, since it is an interesting question, I will provide an answer, at the risk of both answer and question being deleted.

Rock (stones, minerals) can be made into spheres in a very ingeneous way.
We have a rotating drum very similar to a clothes dryer.  Inside, we put the rock or rocks intended to be cut/made into spheres.  We add coarse abrasives,  like sand, crushed diamond... depending on the material the rock is made of.  We then let the drum rotate for a long time until the rock is spherical.  However the surface will still be rough.  If we want that smooth, we have to replace the abrasive completely with a finer grade of abrasive, progressively, until the abrasive produces a smooth surface on the rock.

In fact, a machine based on the same principles is used to peel potatoes.  Nowadays, most potato chips are done in factories and most of them not peeled.

Im pretty sure it would be 6 purple rectangles.