Use the [ and ] keys to cycle between demos.
The initial page lets you compare the different color spaces and how each one shows the same color description.
Describe colors using SimplePalette's syntax in the text fields. This looks like "dullest red purple" or "lighter rich brown". The adjectives are "light", "dark", "rich", and "dull"; these can be made stronger by adding "er", "est", or "most" to the end (really any 2, 3, or 4 letters will work).
The colors (with names and previews) are described on this page.