Fifteen circles oscillate vertically along a sine wave, their radii pulsing in a related rhythm as time advances. The animation runs continuously, with the wave’s speed steadily increasing. This example demonstrates D3’s selection and join API, using `select('body').append('svg')` to build the scene, `svg.selectAll('circle').data(data).join('circle')` to update circles, and a similar path join to draw connecting lines between adjacent points. The data is generated procedurally with `makeData`, computing x positions from a fixed spacing and y positions from `Math.sin`.