Derived from the Greek word (Haptesthai) meaning 'touch' or 'contact', haptic relates to the way in which humans interact by touch with the world around them. Artists use haptic technology to give the sensation of a physical presence to a virtual object. This can be manifested in several ways: via vibrations in sound installations or using computer software that has input devices that offer touch feedback. An example of this is a computer program that enables the user to paint a picture using virtual 3D brushes.