Yoneda structures on 2-categories Journal of Algebra

An ash tray of circular shape formed with a circular projecting flange bounding an annular recess, in which sand may be placed, with a central cup section in which a bracket is fitted. The bracket is shaped with radial spokes, each terminating in an open ring of a size to fit a cigarette tip, with the spokes joined to a central open ring of a size to fit about a cigar tip. The spokes serve to hold a pipe of a varying size in place, depending on the placement of the pipe. The bracket is mounted to the inner sides of the cup so as to be raised above the bottom wall of the cup, to permit placement of sand in the cup bottom.