And then if we look at these troughs right here, or these antinodes, rather, those are going to be areas where we have total constructive interference.
A standing wave in a pipe with two open ends is kind of the opposite, of the wave with two fixed ends: Instead of having a node at each end, it has an antinode at each end.
The second-simplest standing wave you can have on a string with two fixed ends has 3 nodes -- one at each end, and one in the middle -- plus 2 antinodes in between the nodes.