Someone else already said it’s popes, as for how it relates to the comic, it’s the arms.

Frame 1 = 1 arm up
Frame 2 = 2 arms up, one higher than the other
Frame 3 = 2 arms up, the same height
Frame 4 = 1 vertical arm, one horizontal arm.

i.kym-cdn.com/entries/icons/…/lossminimal.jpg