C3 - or "C Cubed" could be an extension to Ken’s CCC. I can’t get the forum to do superscript.

CCC - as long as we don’t start wearing white hoods, we should be OK

XUK is almost symmetrical - I ike that.

Anything along the lines of "CUK" can (and no doubt will be) subverted into something rude.

I like COG as well.