This is a graph of a function proportional to the electric potential in the neighborhood of four charges sitting on the corners of a square. The function is z(x,y)=((1-x)^2+(1-y)^2)^-1+((1-x)^2+(1+y)^2)^-1+((1+x)^2+(1+y)^2)^-1+((1+x)^2+(1-y)^2)^-1.

Twenty years ago I couldn't even print out a quality image of this function since therer were no lasers that could spool an image that big, so I ended up printing to a fax machine.

flow was xls>dat>scad>stl>skp>stl with one netfabb repair and some cropping.

Shout out to thomthom and his shell extension for sketchup: i wouldn't have succeeded in less than 24 hours without it.

Walls are thin, so two shells makes it solid. I had some pulling, but you should be okay if you've covered your machine or have fans going. No support needed if printed at given ratio of scales.