Roy Lewallen wrote in
treetonline:

Put two violins close together and pluck the string of one. The
corresponding string of the other will vibrate. THROUGH AIR!

Then consider the (say) three strings of a piano note, and that if their
resonant frequencies are close enough, they vibrate in phase (that implies
at the same frequency of course), well they do until the amplitude of
vibration dies down sufficiently and they 'unlock' and vibrate
independently.

You mind has just begun to boggle.

Now, somehow I can see this being used to explain an antenna.

I hear the behaviour of a string in a violin being used to explain why
resonant antennas are just better, and how they "fairly suck the power out
of the transmitter, like a string sucks the power out of the bow".

Owen