Overview of the Civilian Drone Market (DIY Drones) — Six categories: toy quadcopters; FPV/racing; consumer camera drones; prosumer camera drones; consumers, industrial, agricultural, NGO and Research drones; winged and VTOL drones.
How to Turn Complicated Things into Playful Things (Tom Whitwell) — Children are the apex players, at the top of the hierarchy. Only when they’re absent will adults play. […] You know when play is working, because the room gets noisy.
Bottom Up Computer Science — A free, online book designed to teach computer science from the bottom end up. Topics covered include binary and binary logic, operating systems internals, toolchain fundamentals, and system library fundamentals.