Expanding Hole Illusion

Open fullscreen view :root { --w: 7vmin; --h: calc(var(--w) / 2); min-height: 100vh; margin: 0; background: radial-gradient(60% 35%, #000 50%, #0000 0) 0 0 / var(--w) var(--w), radial-gradient(60% 35%, #000 50%, #0000 0) var(--h) var(--h) / var(--w) var(--w); &::before { content: ""; width: 85vmin; aspect-ratio: 11/7; background: #000; position: absolute; top: 50%; left: 50%; translate: -50% -50%; border-radius: 50%; filter: blur(5vw); } }

About This Illusion

This is a trippy optical illusion. It is completely static, yet it looks like the black hole at the center is expanding - especially when you are not looking at it directly, creating the sensation of falling into a pit.

From a coding perspective, this one was very simple: a background pattern made with two radial gradients, plus a blurred pseudo-element for the "expanding" hole.

Try This