Khan Academy
Khan Academy: Bonus: Equations for Points in Subdivision
Points on the control arm: Let's start with a shape with four control points, AAAA, BBBB, CCCC and DDDD, then use subdivision with weights (1,1)(1, 1)(1,1)left parenthesis, 1, comma, 1, right parenthesis.
Khan Academy
Khan Academy: Bonus: Equations for Points in Subdivision
This lesson provides examples that illustrate equations for points in subdivision.