When two undulatory movements with equal characteristics cross the same region in space, their waves experience superposition, i.e. there is interference. You have sometimes been fully conscious of this phenomenon when you cannot hear your favourite radio station clearly because of interference from another station.
This is due to a particular phenomenon of waves. Particles, when they collide, mutually divert each other; only waves can pass through each other and then go on their way as if nothing had happened. To understand this phenomenon, activate the following visual:

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