Relation R:
R(a,a), R(a,b)
R(b,b)
R(0,x) x = 0, a, b, 1
R(x,1) x = 0, a, b, 1

Orthosupplement:
0 a b 1
0 b a 1

Candidates to fill: (0, a), (0, b), (0, 1)*, (a, a), (a, b)*