For example {HEAD ~ a large cell} of {TAIL ~ each primary color} and black can be placed in the four corners 
of
For example { HEAD ~ a large cell } of { TAIL ~ each primary color } and black can be placed in the four corners
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH