This example demonstrates a static SVG rectangle that animates its width in response to a button click. The visualization uses D3.js to select the HTML body element, create an SVG container, and draw a rectangle. When the button triggers the `trigger()` function, the rectangle transitions its `width` attribute from 50 to 400 over a duration of 2000 milliseconds with a 100-millisecond delay, before being removed from the scene. The page relies on inline JavaScript and D3’s selection and transition APIs.