The color wheel is a diagram which serves as a tool representing many aspects of colors and how they work together. The wheel is split into warm and cool colors and also displays color relationships.  Complementary colors, which create contrast, are opposite each other on the wheel and analogous colors, which create harmony, are next to each other. Mixing of colors is also represented.  Primary colors (red, yellow, blue) when mixed in equal parts, form the secondary colors (orange, green, violet). Tertiary colors (RO, YO, YG, BG, BV RV) are then made by mixing primary and secondary colors respectively.