Wondering around the university I found a suspicious "Top Secret" cardboard folder, probably another cheap ad to attract students. To my surprise, it turned out to be a cardboard turntable, made to manually reproduce a 45 rpm vinyl with some kind of musical puzzle inside. What a wonderful way to recruit students!
I was eager to check the contents of the record. However, when I tried to play it, the cardboard turntable showed some tuning problems which made the task of listening the high notes a misery. Since I love mysteries and crafting, I decided to build my own with paper, hoping to get better results, and so I did!