Believe it or not, billiard tables have been constructed in almost every shape imaginable. I have a collection of patent records that includes hexagonal billiard tables (as early as the 1870's), octagonal billiard tables, oval tables, hour-glass shaped tables, tables with "obstacle courses" etc etc etc.... and most if not all of them are extinct.
Not that it really matters in the big scheme of life, but if I were that person, I'd hold onto that table just for rarity's sake.