This level and level 13, Beg, Borrow, and Steal were both laid out by Tim Thomas, then textured and populated by Clund. Tim was with us only briefly, and his... fractally generated? maps were extremely impressive to say the least.
The name Hex Level 73 actually comes from the resignation email he sent Chris and I. He told us that he was moving across country because of work, and wouldn't have any more time to work on Rubicon. As a parting gift he attached an unfinished map that he had been working on, named Hex Level 73. His explanation for the name was that the premise for this level was lots and lots of hexagonal structures all tesselated and layered, hence Hex level. Tim would save multiple copies of levels he was working on, so that he had a little trail of files leading from the very first few polygons of a map to the finished product. The last version he saved before his retirement was #73, hence, "Hex Level 73."