These widgets were made to illustrate the construction of cubic and quadratic Bézier curves. Each line is divided into segments in the ratio determined by the slider. The segments of each line are coloured with the colours used in the slider, to point out that they are indeed in the same ratio. In contrast to the curve (red), those colours are muted to indicate that they are auxiliary to the main focus of interest, the curve.

Drag the control points (dark) and the slider to change the configurations.