Determine rolled value on CSS 3D dice?

Question

css

Here - codepen.io/anon/pen/YweWXj I implemented a random value drop on a 3D CSS cube by setting it to a random (multiple of 90) value for rotateX, rotateY and rotateZ (mouse over the cube for this to happen). Tell me how to determine which side the cube fell out? I understand that you need to use the RPM values ​​for each axis, but I can’t come up with the algorithm itself. Thank you in advance.

Answer 1

My cube only spins once and doesn't want to anymore (