Table 4 Statistics, classification and coding of the design form of the sample

A

Bowl bottom

Flat foot(a1), high foot(a2), ring foot(a3), round bottom(a4)

B

Bowl wall

Slant belly(b1), deep belly(b2), arc belly(b3)

C

Bowl lid

Arched(c1), knob-style(c2), cover-style(c3)

D

Bowl mouth

Petal-shaped(d1), flaring mouth(d2), lip mouth(d3), converging mouth(d4),flared mouth(d5), wide mouth(d6), rolled mouth(d7)