Love it, that's a fantastic image for these. As a musician intimately aware of how vibrating strings work, the vibrating bubble is a perfect analogy, it seems.
Musicians: see also radial planar circular harmonics, e.g. drums. This is a halfway point in between vibrating strings and vibrating bubbles. It’s highly applicable in music and is easier to understand and visualize than 3d basis functions; maybe a nice stepping stone.