. It has to do with the way chinese food are eaten and served. Chinese food are usually served with many dishes on the table at one time. You will then eat with your bowl of rice together with the chinese dishes on the table. If there are many people, it makes more sense for the table to be rounded so that each person can pick up the food easily from any position. Thus, it facilitates ease of eating. In comparison, western dishes are usually served to one person individually and focused on "one to one" eating. That's why western tables are usually squarish or rectangular.