He made a kind of fishing line for passing notes to adjacent cells by unwinding the elastic from his boxer shorts, though it was contraband and would be confiscated.
They discovered that by shifting the "phase" of light so that the peaks of one wave line up with the valleys of an adjacent one, the two cancel each other, creating "shadows" between waves that are smaller than the waves themselves(see diagram, p. 141).
They discovered that, by shifting the "phase" of light so that the peaks of one wave line up with the valleys of an adjacent wave, the two waves cancel each other out, creating "shadows" between waves that are smaller than the waves themselves(see chart).