This is a simulated Riffle Shuffle on an ordinary 52-card deck. It's based on the Gilbert-Shannon-Reeds statistical model of a Riffle Shuffle as described in the Bayer and Diaconis paper (1992).
The borders of the cards are color coded indicating which packet the card came from: Black for left; Orange for right.
A dotted line will appear in the previous shuffle indicating where that deck was cut into the two packets.
Notice how much order remains in the deck for the first several shuffles.