I did it all by hand in HTML canvas. I have spent a long time making such things for years. My day job is making a canvas-based Diagramming library so I have some practice.
If you click on it the scene creates more objects by the way. And if you right-click and drag you can move them around.
If you click on it the scene creates more objects by the way. And if you right-click and drag you can move them around.