Fork of Circles with D3
This example displays a dynamic SVG landscape composed of seven multicolored circles and a green rectangle. It demonstrates the D3 General Update Pattern through method chaining, where `selectAll`, `data`, and `join` from the `d3` module manage both SVG elements. The circles of varying sizes and colors sit against a cyan background, while a green rect forms a lower band. The code uses the `select` function's imperative API to set attributes like `cx`, `cy`, `r`, `fill`, and `width` based on array data.