Can i add multiple docks?

Can I add multiple docks?

I managed to once, by pressing the fn key and something else (sadly, I cannot remember.)
One dock was purple and the other was white. the purple was on the right and the white was on the left.

(it may have been fn + right click on the dock.)(also, it may not have been the fn key, but command or alt)

I’m not looking to mimic that, but any method that allows me to have multiple docks with separate apps on them.