I need to understand SVG better. I can do basic stuff. For example
<svg width="100" height="100">
<rect x="0" y="0" height="40" width="20"
fill="green" stroke="red" stroke-width="8"/>
</svg>
gives me a little green square with a red border:
Perhaps I should link to a page for trying out SVG. I've a tutorial to work through, and a reference to consult. I particularly want to look at Viewports
I'll try a little JavaScript.