A single SVG canvas displays two red rectangles with black borders. One rectangle is large and centered, while the other is small and placed in the corner. The visualization demonstrates CSS transitions applied to SVG elements, where the `transition: all 3000ms` rule animates any property changes over three seconds. When the mouse hovers over a rectangle, the `rect:hover` pseudo-class triggers a change in fill color to green and increases the stroke-width to 150 pixels.