The example shows a single red circle that remains centered within a blue container as the browser window resizes, turning blue after any size change. It uses d3.v4 with SVG rendering to bind data to a circle element, positioning it based on the container’s client dimensions. A general update pattern with `merge` and `exit` handles resizing, while a counter tracks window width changes to prevent the radius from shrinking below its initial value. The data is hardcoded in the script, and the visualization is built with Blockbuilder.