| colors2d | Map values to a 2D legend interpolated from 4 corner colors. | 
| colors3d | Map values to a 3D legend in RGB colorspace. | 
| colorwheel2d | Map values to a 2D colorwheel legend. | 
| distant_colors | Palettes of dissimilar colors in RGB space. | 
| polarize | Internal function converting x-y do distance-angle. |