Situation 2: the pulses are given in phase opposition.
Again, once the waves meet, their amplitudes will be summed, but we can see that the amplitude wave direction is negative relative to the vertical axis, so <0. Therefore, the resulting pulse will have amplitude equal to the difference between the two amplitudes:
Since the negative signal is linked to the amplitude and elongation of the wave in the negative direction.
After the meeting, each one goes in its initial direction, with its initial characteristics preserved.
This type of overlap is called destructive interference, as overlap causes the amplitude to be momentarily reduced in modulus.