#44 Playing Noggin'April 28, 2017
In the median society we call them “Shields”, but the hobos call them “Noggins”. (The apostrophe disappears somewhere on the way to plurality. Not that the hobos would know to write it in the singular form in the first place...)
Anyway, that is probably where the game gets its name.
There are some slight variations of the rules, mostly regarding how many times you are allowed to attempt to find the Shields or whether just finding one (and keeping it intact) will make you win the game.
Why it has to be thirty cards when a set contains eleven cards and three sets are used? One explanation could be that the hobos rarely have full sets in their possession and they just use everything they have available. And then someone decided the game needed official rules and thirty was the most common number of cards an average hobo had.