Bro, it doesn't mean anything. It just means that they have 48 zodiac signs. What Hussie's going for is not a theme with the zodiac, but the number 12. In human history the number 12 is an important number in nearly every religion and mythological belief. It's just that the symbols on the troll's shirts (which could be anything from band logos to FLARP symbols to the trolls), is burned into the existence of the kid's universe, so, humans, trying to make sense of this primal desire to remember their 12 creators, assign the number 12 to shit.