The g-color-swatch renders a color. It can be editable and allows the user to choose the color, or it can simply show a color directly or one derived from another color.
An editable swatch's value can be reflected in another's
See the Pen Editable Swatch and Mirroring by Dave Copeland (@davetron5000) on CodePen.
A swatch can be derived from another via algorithm
See the Pen Derived Swatches by Dave Copeland (@davetron5000) on CodePen.
Combining Derivations and Styling
See the Pen Multiple Derived Swatches w/ Styling by Dave Copeland (@davetron5000) on CodePen.