My friend Spencer Chen, CMO of BRD and Blockset, blew up Twitter a while back by observing that many hot tech companies have apparently borrowed their logos from previous designs. While there is a finite set of possibilities specifically for logos based on a single character, the resemblances are striking and uncanny nonetheless. Furthermore, the logos of Airbnb, Beats, Flipboard and Medium all seem to be based on designs featured in a 1989 design book, “Trademarks & Symbols of the World:…