Notation infE := (sameP afix1P eqP).

Lemma card_n2_3 : forall x y z t u v: cube, uniq [:: x; y; z; t; u; v] ->
#|[set p : col_cubes | (p x == p y) && (p y == p z)&& (p t == p u )
&& (p u== p v)]|  = (n ^ 2)%N.