The whole film is data and two numbers: you and cpu (0 rock, 1 paper, 2 scissors). The hands and the ending are chosen by expressions on them, for example the win ending has alpha: 'win' where win is step(0.5, 1 - abs(mod(you - cpu, 3) - 1)). The page does one thing: when the playhead goes from after the SHOOT! to before it (a seek back, or the loop starting again) it calls movie.setVars({ cpu }) with a new random hand. After the SHOOT! nothing changes, so every seek there lands on the same ending. The same film as a file: pixi-effects render janken.html --var you=1 --var cpu=0 --var jingle=chime (jingle is the ending's sound: chime for a win, hit for a loss, beep for a draw).