I feel like I should already know this one, but is there a command line way to add an atom at specified coordinates? or at screen center? I thought there was a new-ish pseudoatom functionality but I can't seem to find or recall details. Can one specificy atom type as well?

I was looking to annotate a structure with some graphic landmarks. I've used CGO spheres, etc. in the past but they aren't easily recolored and such interactively after the fact so I'd prefer using dummy atoms of some sort.