@SharonCullars 's suggestion about round business cards made me wonder if double-sided (round) coasters exist, and they do. – resin, acrylic, laminated paper … this opens up opportunities for businesses, or just lets customers be twice as creative.
Thank you for your consideration.
PS. I would have liked to have posted this suggestion under New Product Suggestions, but I can’t find that subsection under Ideas & Suggestions.