Erasing part of what you have created might seem contradictory at first. But when you, for example, try to create a semicircle in SVG, you will find out the use of the following properties quickly: ...

<svg id="svg-root" width="100%" height="100%" viewBox="0 0 480 360" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> ...