A list of numbers or diagrams that are in a particular order ... Look at the difference between one pattern and the next in the sequence. Here, 1 yellow circle and 2 red squares are being added ...

Gowravaram, Nihal, and Ravi Jagadeesan. "Beyond Alternating Permutations: Pattern Avoidance in Young Diagrams and Tableaux." #P17. Electronic Journal of Combinatorics 20, no. 4 (2013).