Pardon the off-topic comment, but is anyone else finding the discussed web page to be sluggish to the point of unusability? (This is on Firefox 67, on Windows 7

Pardon the off-topic comment, but is anyone else finding the discussed web page to be sluggish to the point of unusability? (This is on Firefox 67, on Windows 7.) I'm not talking about page load time; once the page has finished loading: - trying to scroll the page using arrow keys or Page Up/Down keys takes several seconds between key press and response - when dragging the scroll bar manually, the new scrolled-in area is blank white for several seconds before finally filling in with content - even right-click, or click-drag to select text, takes a few seconds to respond I tried disabling javascript on the page, but it makes no difference, so it's not some runaway script. I'm guessing that maybe there are some very high resolution Mandelbrot images that are being scaled in the browser?