There is no "usual": you can define them geometrically (as lerps of lerps), symbolically (as polynomials), or even algebraically (as power matrix operations). A

There is no "usual": you can define them geometrically (as lerps of lerps), symbolically (as polynomials), or even algebraically (as power matrix operations). All three are covered over on https://pomax.github.io/bezierinfo https://pomax.github.io/bezierinfo which was on HN yesterday =D