Segment / Either / Or

Invisible Form 

(destroyed)

The inside of the circle line and the outside of the cubic volume of wood are one.

The circle segments in wood are the only visible part of sets of interlocking circles. The idea of the full circles in the top half are interlocked with circles on adjacent sides in the bottom half, creating a twist). The spectator must chose between mutually exclusive  ideas: the idea of the full circle in the mind and the idea (form) in wood. 

role of the volume and the surface of the cubic piece of wood

role of the border / the surface cut