A Burger that has different dressings on different sides

I thought a cheese, ham or chicken burger could be dressed in two halves. One half could be lettice and mayo, the other ketchup onions and pickle, as an example. It could be an interesting change and mean different bites are different dressings and taste. Theres a lot of different combos that would be possible. Some could be set combinations or people requesting how they want it done. Its cheap to implement, an interesting selling point and a change from the usual for the customer.