The roots of experimental pop can be traced to Sgt. Pepper-era Beatles, the progressive rock of ELO and Brian Eno's '70s near-pop period. Experimental pop combines traditional ideas of tuneful melody and phrasing and turns them on their ear with artful tinkering and cerebral prodding. By the mid-'90s, the Flaming Lips, Radiohead and Bjork were among the most successful commercial acts to revamp the style by adding elements of psychedelia, surrealism or electronic ambience to pop. This skewed take on mainstream music was further practiced by indie bands such as Magnetic Fields, Mercury Rev, Yo La Tengo and Blonde Redhead.