The technique of action painting was used by artists of which post–world war ii art movement

Pop art (Andy Warhol, Lichtenstein, pollock)

It depends on what type of third separates the three notes.for example: if you have two mayor thirds is an "aumented chord"if you have two minor thirds is an "diminued chord"if you have one mayor first and then one minor is a "mayor chord"and inverted is a "minor chord"