The appearance and shape of sesamoid bones within a tendon or ligament wrapping around a joint are understood to be influenced by both genetic and epigenetic factors. Ostriches (Struthio camelus) possess two sesamoid patellae (kneecaps). one of which (the distal patella) is unique to their lineage. making them a good model for investigating sesamoid tissue development and evolution. https://www.elphonsolam.com/product-category/thank-you-cards/