Above: A hexagonal (six-sided) snow crystal, classified as a stellar dendrite. This crystal was photographed with an Olympus TG-6 camera after it landed on the sleeve of the authors fleece jacket.

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A prism has a constant cross-section throughout its length. When the cross-section is a triangle, the prism is called a triangular prism. When the cross-section is a hexagon, the prism is called a ...