Colour wheels are a visual representation of each colour and their many combinations.
Red, yellow, and blue cannot be created by combining other colours together, but are used to make other colours.
Green, orange, and purple are made by combining primary colours. Green is made by mixing blue and yellow, orange is made with yellow and red, and purple is made with blue and red.
Blue-green, red-purple, yellow-orange, blue-purple, yellow-green, and red-orange are made by mixing each primary and secondary colour together.
Colour wheels are a helpful tool to show visually pleasing complementary and analogous colour combinations.
Complementary colours are any two that are found directly opposite one another on the colour wheel. For example, yellow and purple, red and green, orange and blue.
Analogous colours are found side-by-side on a 12 part colour wheel. For example, blue-green, yellow-green, and yellow.