These fins will divert solid waste towards the rear of the toilet while allowing liquid waste to pass through. They will be coated with a superhydrophobic material to assure that no residue remains. Here is an exploded view of the toilet with the fins exposed:

Here is a view of the fins as seen from above through the toilet seat:

Here is an isolated view of the fins.

Note how they are shaped to guide liquid to run off of the bottom center corner.