Do you mean something like this https://www.amazon.com/Hanperal-Adjustable-Square-Stainless-Bakeware/dp/B0178Z8CGS/ref=mp_s_a_1_4?dchild=1&keywords=adjustable+cake+pans&qid=1606759473&sr=8-4? I see them pretty often in cake/cooking shops so you might be able to buy them locally too