I watch the electric vehicle YouTube channel 'Transport Evolved', and the creator has had some interesting issues with her new iMac Pro. In some "behind the scenes" videos on her second channel, she has shown that her "backup" computer is a pre-unibody 15" MacBook Pro. That seemed 'retro' enough, but she just posted another behind-the-scenes video, and she has a PowerBook G3 Pismo in active use in the background! (Then presents "the PowerBook that saved the world" PowerBook 5300, as well, but the Pismo appears to be in actual active use.)
