Bones, burls, gourds. Tagua nut and ostrich eggshell. Horn, antler, fossil ivory. Shell, stone, and hide. When you start to think about it, nature offers all kinds of readymade enclosures, and materials for enclosures, that most folks don’t usually think about. Case in point, this Tiki-tastic coconut shell mini-amp, which uses the classic Little Gem amplifier circuit.