From woodworker and ITP student Ben Light’s site:

A spoil board is sacrificial material that’s used underneath the material you want to cut on a CNC machine. This ensures a better through cut and is usually MDF. I’ve noticed that when the spoil boards are all used up at ITP, some really amazing patterns are formed.

By making careful choices in his display of this found art, Ben really stumbled onto something beautiful that normally would have ended up in the dumpster. It would have been a shame to see this piece spoiled in such a way.