Concentric rings from one or more sources. Wavelength is the gap between crests; sources scatter from the seed.
Concentric rings from one or more sources. Wavelength is the gap between crests; sources scatter from the seed. A radial slice is just a decaying 1D wave.
wave
1D foldA radial slice: crest, trough, crest. The sheet is this line spun around each source.