Diana: It just became increasingly clear that something rather strange was happening. The pattern I devised consisted of two tones that were spaced an octave apart, and alternated repeatedly. The right ear received the sequence high tone, low tone, high tone, low tone over, [SFX: play sequence]. And at the same time, the left ear received low tone, high tone, low tone, high tone [SFX: play sequence] over, and over again. When I put on my earphones I was astonished. A single tone appeared to be switching back and forth, from ear to ear and at the same time, its pitch appeared to be switching back and forth from high to low.