About the definition of "artificial intelligence". Mozi said, "Hey, a China person is as long." The word "er" here is a circle. Mozi pointed out that the circle can be drawn with compasses or checked with compasses. Compasses have been widely used before Mozi, but it is Mozi's contribution to give a precise definition of circle. Mozi's definition of circle is exactly the same as that in Euclid's Geometry.