Two wave pulses in a string have amplitudes that have exactly the same size, and when they are in the same region, there is total destructive intereference -- a picture of the string at that moment shows it to be entirely flat. A few seconds later, what does the string look like? Two wave pulses in a string have amplitudes that have exactly the same size, and when they are in the same region, there is total destructive intereference -- a picture of the string at that moment shows it to be entirely flat. A few seconds later, what does the string look like? Only one of the pulses remains Both pulses remain, but they are permanently deformed The string is still totally flat Both pulses remain, and they have retained their initial shapes