(L) appearances of ABBB in the 5x5 grid: 40; size 25; concentration = 40/25
(U) q = 20; nonzero table entries: 1222; max |G| = 29
(U) max over all 65536 patterns of 20*q*(Psi0 + D(X) + D(X^T)) = 640  <=  32*q = 640
(U) number of patterns with equality: 568
CERTIFICATE VALID: every 4x4 pattern satisfies Psi0 + D(X) + D(X^T) <= 8/5; hence C_2(ABBB) <= 8/5, and (L) gives equality.
