Christmas tree Macy's Great Tree in Atlanta (since 1948), the Rockefeller Center Christmas Tree in New York City, and the large Christmas tree at Victoria Square in Adelaide. The use of fire retardant allows many indoor public areas to place real trees and be compliant with code. Licensed applicants of fire retardant solution spray the tree, tag the tree, and provide a certificate for inspection. Real trees are popular with high end visual merchandising displays around the world. Leading global retailers such as Apple often place real trees in their window displays. In 2009, Apple placed two Fraser fir trees in every
Noble polyhedron 'dual' covers both kinds. The dual of a noble polyhedron is also noble. Many are also self-dual: Noble polyhedron A noble polyhedron is one which is isohedral (all faces the same) and isogonal (all vertices the same). They were first studied in any depth by Hess and Bruckner in late 19th century, and later by Grünbaum. There are four main classes of noble polyhedra: If we allow some of Grünbaum's stranger constructions as polyhedra, then we have two more infinite series of toroids: We can distinguish between dual structural forms (topologies) on the one hand, and dual geometrical arrangements when