The colour wheel or colour circle is the basic tool for combining colours. The first circular colour diagram was designed by Sir Isaac Newton in 1666. The colour wheel is designed so that virtually any colours you pick from it will look good together.
Over the years, many variations of the basic design have been made, but the most common version is a wheel of 12 colours based on the RYB (or artistic) colour model. Traditionally, there are a number of colour combinations that are considered especially pleasing. These are called colour harmonies or colour chords and they consist of two or more colours with a fixed relation in the colour wheel.