Obtuse Angle
An Angle greater than 
Radians (90°).
- Spun Knot
- Squarable
- Square
- Square Bracket Polynomial
- Square Cupola
- Square Curve
- Square Cutting
- Squared
- Squared Square
- Square-Free
- Squarefree
- Butterfly Catastrophe
- Butterfly Curve
- Butterfly Effect
- Butterfly Fractal
- Butterfly Polyiamond
- Butterfly Theorem
- Bäcklund Transformation
- Bézier Curve
- Bézier Spline
- C
- C*
- Cable Knot
- Cactus Fractal
- Cake Cutting