 One example that van Bendegem cites dates back to work done by the 19th-century Belgian physicist Plateau on minimal surface area problems. By building various geometrical shapes out of wire and dipping these wire frames into a soap solution, Plateau was able to answer specific questions about the minimum surface bounding various particular shapes, and—eventually—to formulate some general principles governing the configurations of such  surfaces.[6]  One way of understanding what is going on in this example is that a physical experiment—the dipping of a wire frame into a soap solution—is producing results that are directly relevant to a certain class of mathematical problem. The main drawback of this way of characterizing experimental mathematics is that it is too restrictive. Examples of the sort van Bendegem cites are extremely rare, hence the impact of mathematical experiments of this sort on actual mathematical practice can only be very limited at best. Moreover, it cannot be only this, literal sense of experiment that mathematicians have in mind when they talk about—and do—experimental mathematics.