Which Basket?

I ordered 3 steamed buns… plain, brown sugar, and sesame. The vendor looked like she was playing a game of stack the baskets as she rearranged the towers to find my order. She picked up three baskets at a time revealing the sesame underneath then restacked, moved over to the side, and down four baskets to find the brown sugar. She knew where each one was and never opened the wrong basket. A true expert!