"When I was still in the Yardbirds, our producer Mickie Most would always try to get us to record all these horrible songs. He would say, 'Oh, c'mon, just try it. If the song is bad we won't release it.' And, of course, it would always get released! [laughs] During one session, we were recording 'Ten Little Indians,' which was an extremely silly song that featured a truly awful brass arrangement. In fact the whole track sounded terrible. In a desperate attempt to salvage it, I hit upon an idea. I said, 'Look, turn the tape over and employ the echo for the brass on a spare track. Then turn it back over and we'll get the echo preceding the signal.' The result was very interesting - it made the track sound like it was going backwards."
-  "Interview with Jimmy Page" Guitar World magazine (1993)