A mathemetician and an engineer attend a lecture by a physicist. The topic concerns Kulza-Klein theories involving physical processes that occur in spaces with dimensions of 9, 12 and even higher. The mathemetician is sitting, clearly enjoying the lecture, while the engineer is frowning and looking generally confused and puzzled. By the end the engineer has a terrible headache. At the end, the mathemetician comments about the wonderful lecture. The engineer says "How do you understand this stuff?" The mathematician replies: "I just visualize the process." But the engineer isn't satisfied: "How can you POSSIBLY visualize something that occurs in 9-dimensional space?" "Ah," says the mathematician, "it's easy, really. First visualize it in N-dimensional space, then let N go to 9."