At 36 minutes and 8 seconds as the camera pans down you can see lines drawn on the black board on the right of the screen. Until 36 minutes 40 seconds when it cut backs to him from the candle to show the black board back the other way around which he proceeds to turn around without those lines and over the next few minutes draw the lines that were on the board between 36 minutes 8 seconds and 36 minutes 40 seconds.