What if you could travel without luggage and “print” what you need upon arrival? The Finnish 3-D printing pioneer Janne Kyttanen is working on the idea. His is one of a hundred projects catalogued in the heavily illustrated “Printing Things: Visions and Essentials for 3D Printing” (Gestalten). Editors Claire Warnier, Dries Verbruggen, Sven Ehmann, and Robert Klanten have gathered a wonderland of 3D creations. There’s a peace drone that wears a goofy smile and disseminates painkillers, an igloo-like structure made out of salt harvested from San Francisco Bay, and a NASA-backed effort to launch satellites equipped with 3D printers that can build structures in space.