SVG Fundamentals
This example demonstrates a basic SVG scene composed of three primitive shapes: a circle, a rectangle, and a line, all placed on a 1000 by 1000 canvas. The shapes show how different SVG attributes control appearance, such as `fill`, `stroke`, `stroke-width`, and geometric properties like `cx`, `cy`, `r`, `x`, `y`, `width`, and `height`. The explicit `stroke="red"` on the `<svg>` element sets a default that is overridden by individual shapes, like the rectangle's blue stroke. The example uses plain SVG markup within an HTML file, with no JavaScript or external libraries.