(This description will probably be easier to understand if you look at the image first.) The image "sponge4.jpg" is a structure called a Menger sponge. It is created by cutting square holes in the center of a cube along all three axes. The width of the holes is 1/3 the cube's length so that the resulting structure appears as if it could be made of 20 smaller cubes each having a length of 1/3 the length of the original cube. This is called a first iteration sponge. Each of the smaller cubes has its center portions cut out just as the original cube did, producing a 2nd iteration sponge. The sponge in the image is a 4th iteration sponge. The Menger sponge is interesting because an infinite number of iterations will produce a structure that has no volume, yet has an infinite surface area. This is an image that I've wanted to make for a while but until now I had neither the time nor the motivation to do it. I thought that this would be appropriate for the topic of "science" because it falls into the science of topology. To create the image I used Excel to generate the end points for the boxes used to cut out portions of the original cube. Each of the boxes extends just beyond the length of the original base cube keeping the total number of primitives lower than it would be if I tried to treat each itieration as a group of successively smaller cubes. Still, there are almost 2500 objects in the scene. I exported the Excel sheet to a text file and modified it by hand to add a plane, camera, and a couple lights. I used POV to trace the image on a Sparc 10, which took a little over 100 hours. All switches were default except for anti-aliasing which was 0.05. The image turned out a little darker than I had hoped it would, but I'm not about to trace it again! I tried to decrease the trace time by adding a bounding box around the sponge, but I'd be interested in suggestions to better use bounding boxes in a case such as this with a large number of objects in one CSG object. Matt (M.Loiselle@IEEE.org)