2 squares a & b have always 2 orthogonal intersection squar…
2 squares a & b have always 2 orthogonal intersection squares s1 & s2.
. | . . . | . .
--1-------b----
. | . . . | . .
. | . . . | . .
. | . . . | . .
. | . . . | . .
--a-------2----
. | . . . | . .
> s1 := (b & 56) + (a & 7);
> s2 := (a & 56) + (b & 7);