Harpalus Crater in Mare Frigoris. 3 degrees of latitude by about 5 in longitude, cut into a hard maple block 9.5″ (242mm) square by 1″ (25mm) thick. If this were a photograph of the lunar surface, the resolution would be less than 0.2 arcseconds. From SLDEM dataset. See http://wp.me/poDQ-fw for earlier attempts at imaging Harpalus.