How can I make a button which swaps between 3 background colors?

So I'm trying to figure out how to have the click of a button swap between 3 background colors in a windows application form. Managed to make it swap between 2, but struggling to move up to three.

The result of ~30 minutes of trying everything that came to mind: https://prnt.sc/1rka67i

The 2 color variation: https://prnt.sc/1rkakrm