The Elbow cassette player concept is as impractical as a cassette tape

Elbow is a clever, perhaps too clever, cassette player concept that was unveiled by the "audiovisual art organization" BrainMonk a year ago. Now BrainMonk is looking into the feasibility of actually building it, and has put out a PDF that details the necessary components, according to Music Crowns.
The concept itself is simple: what if a cassette player didn't have any of that nasty boxy stuff that protects the cassette? Elbow, were it to exist, uses a single pulley to drive the tape, and it tra