Wow! I didn't know that carom boards came in different shapes. I saw a photo on the Web from a carom tournament in the US, where all the competitors appeared to be emigrés from the Indian subcontinent, and all the boards visible (about 12) were square. My Dad would be aghast to hear that you thumped the pieces - he spent years trying, wih limited success, to teach me a very refined, silky-smooth flicking action with index and middle finger!