Make terminals (windows) staggered

[Harry Putnam]

What can I set so that when I call an xterm with my custom keybinding
(C-S-t) It comes up staggered geometrically from any others I've
called?

Currently they all go to exactly the same spot since the geometry
setting is contained in my keycombo call to xterm.
(Key t   A CS Exec xterm -geometry +600+400)

I'd like them to appear in some regular (1/2 diagonal) staggered stack.