p173fig04.50 This figure illustrates how a closed boundary can be formed in a prescribed depth due to addition of binocular and monocular boundaries, but not at other depths.<BR>|| How are closed 3D boundaries formed? V1 Binocular, V2 boundary, V2 surface; Prediction: monocular and horizontal boundaries are added to ALL binocular boundaries along the line of sight.  Regions that are surrounded by a CLOSED boundary can <I>depth-selectively</i> contain filling-in of lightness and colored signals.