分类 1、按形状分 Disk with Slot Semi Disk Disk Sector 明 &ao Elliptical Ring Semi Ring Ring Sector Square Disk Pentagon Hexagonal with Eccentric Inner Circle Circular Ring Rectangle Ellipse H-Shape U-Shape L-Shape Equilateral Triangle Ring Rectangular Rectangular with Right-Angled a Ring Inner Circle Isosceles Triangle Cross-Junction T-Shape Trapezoidal UESTCUESTC 分类 1、按形状分