This example demonstrates basic DOM selection and manipulation with D3. It binds an array of score data to five SVG circles and uses `d3.select` and `d3.selectAll` to modify their attributes dynamically. The code applies styles like `fill` and `radius` through `.style` and `.attr`, including random radii and vertical offsets. A separate message div is updated with `d3.select('#message').text()`, while the third circle receives a CSS class via `.classed()` to highlight it.