The color wheel was invented in 1666 by Isaac Newton, who mapped the color spectrum onto a circle. The color wheel is the basis of color theory, because it shows the relationship between colors.
Colors that look good together are called a color harmony. Artists and designers use these to create a particular look or feel. You can use a color wheel to find color harmonies by using the rules of color combinations. Color combinations determine the relative positions of different colors in order to find colors that create a pleasing effect.