R = {(1,1),(2,1),(3,2),(4,3)}
R2 = R * R = { (1,1), (2,1) , (3,1), (4,2) }
R3 = R2 * R = { (1,1), (2,1), (3,1), (4,1) }
R U R2 U R3 = {(1,1), (2,1) , (3,1), (3,2), (4,1), (4,2),(4,3) }
To find the R*R search for the terms like (X,Y) (Y,Z) which convert to (X,Z).