The Menger SpongeTake a cube, cut it into 27 sub-cubes and remove the centre one and the six face-centres, leaving 20. Do the same to each of those 20. Repeat forever. What’s left has infinite surface area but zero volume, and its “dimension” is not 2 or 3 but log 20 / log 3 ≈ 2.727. Drag to orbit, scroll to zoom. The journey: rather than storing billions of tiny cubes, the shader tests each pixel’s ray by repeatedly folding space into one sub-cube and subtracting a cross-shaped hole — four folds already look infinitely deep.