It would be useful to have a rule that recognizes duplicate products in the shopping cart.
The rule could look something like this: Item same product quantity is equal to 2"
As an application example:
A store operator wants to give a discount on the second product if there are two of them in the shopping cart.

So twice product A and once product B there should be a discount on one of the products A.
Twice product B, but only once product A, there should be a discount on product B.