Every one of them is light: an electric and a magnetic field taking turns, travelling at 299,792,458 metres per second. The only difference along the whole spectrum is how long one wave is — and that single number decides whether it cooks your dinner, shows your bones, or lets you see.
When two waves meet they simply add. Line the crests up and you get a bigger wave; line a crest up with a trough and they cancel to nothing. Noise-cancelling headphones are exactly this, and so are the colours in a soap bubble.