| Kind | Value | annotation | ||
| enumeration | 1_very concave | |||
| enumeration | 2_very concave to concave | |||
| enumeration | 3_concave | |||
| enumeration | 4_concave to flat | |||
| enumeration | 5_flat | |||
| enumeration | 6_flat to convex | |||
| enumeration | 7_convex | |||
| enumeration | 8_convex to very convex | |||
| enumeration | 9_ very convex |