Initially I stared at this GIF for a while caused I sensed something was off.
Then it hit me. In most bikes the front and rear wheels usually have the same number of spokes. The only times you see a different number of spokes in the front and rear wheel is in optimized high performance road bikes. In that case, the front wheel has less spokes in order to balance the weight and force distribution. But because this is a fixie without front brakes, more spokes in the front wheel balance the bike by accounting for the torsional load caused by hipsters doing their skid stops. So you could have noticed that or the fact that there are cards in the rear wheel to know it’s a hipster fixie.