Anonymous ID: 07ff5d Dec. 2, 2018, 8:08 p.m. No.4124325   🗄️.is 🔗kun   >>4432

>>4124280

Consider longitudinal wave –

the vibration propagates along the same direction as wave travel

rather than transversely like all the conventional forms of modulation

You won't find much on this in regular physics books but it's real