This is a simulation that you can download and run on your Windows computer. Below is a screen shot of the simulation demonstrating wave interference. If you decide to download and install the simulation program you will be able to run this simulation on your computer and change the settings shown below. Wave1 and Wave2 are both sinusoidal waves of the same amplitude and wave length. That is why they are able to perfectly cancel themselves out (note how the blue line labeled "1+2" goes flatter as the phase difference nears 180 degrees).
