Gyroid cup - check theory

This gyroid cup is intended to check math fact that gyroid is a 3D surface that splits space into two isolated subspaces. So you can check that you can fill this cup with two liquids that don't mix to each other.
Fill one part of the cup with some liquid. Make sure the other part of the cup is still dry and fill the remaining part with some other liquid.
I plan to use milk and coffee. :)