p391fig11.27 (left image) Each scale can binocularly fuse a subset of spatial scales, with larger scales fusing more scales and closer ones than small scales.  (right image) Cortical hypercolumns enable binocular fusion to occur in a larger scale even as rivalry occurs in a smaller scale.<BR>||  Multiple-scale grouping and size-disparity correlation.  Depth-selective cooperation and competition among multiple scales determines perceived depth: a) Larger scales fuse more depth; b) Simultaneous fusion and rivalry.  Boundary prining using surface contours: Surface-to-boundary feedback from the nearest surface that is surrounded by a connected boundary eliminates redundant boundaries at the same position and further depths.