It's actually a Plot3D. E.g., here are the 720 cubes near the conventional slice: gosper.org/mengslice2.svg You can climb it but for one double-step. --rwg On 2016-03-20 01:38, Dan Asimov wrote:

Wow, Bill, how do you get that amazing 3D effect?

—Dan

...

On Mar 19, 2016, at 10:07 PM, Bill Gosper <billgosper@gmail.com> wrote:

nearest the plane through the center, perpendicular to (2,3,2): gosper.org/mengslice3.svg <http://gosper.org/mengslice3.svg>