Figure 9: Bézier combined polynomial curves to create fully three-dimensionally curved surfaces. Taking a grid of points (black), he established a set of curves in one direction (yellow). Points (blue) at equal proportions along these rails form curves traveling in the opposite direction (pink). Recursively sweeping across the rails at every proportional distance defines a surface. The underlying “net” of points can be easily and intuitively manipulated to shape the resultant surface.