I have this one down as 'totalitarian' or 'control', as in 'the fo█r corners of the E█rth'. That appears to be the definition inferring from context clu█s I've encountered, but My certainty about it isn't total. If accurate, it's more or less a synonym for gr██n except not as an 'effort-in-process' symbol as it's not a [col█r], but rather an established and well-sec█red fact.

Derivatives: [squ█re], [gr█d], [rect█ngle], [ch█ss] (with bl█ck and wh█te and g█me), [c█be] (with s█x), [s█lt] (via [c█be]), [b█x], [pl█ying c█rd] (with g█me and m█sk), [p█per], [p█per money], [ph█tograph], etc.