This example demonstrates four hollow black squares arranged in a row, each of which changes its fill color when hovered over—turning blue, red, green, and gold respectively. The visualization uses raw SVG rectangles with CSS `:hover` pseudo-classes to trigger the color transitions. The page is built with plain HTML and CSS, with no JavaScript libraries, and renders the shapes statically at a fixed size of 960 by 680 pixels. The code includes duplicated rectangle definitions with matching IDs, though only the first set is visible.