There was once a young man, a handsome, moral, and brave young man, dexterous beyond compare, sharp of eye, voracious in the consumption of information and with sagacity and recall to rival that of the wisest of elephants. Oh yes, and he was also a software tester. This preternaturally blessed young man, over the course of time, had occasion to visit many conveniences, both public and private. As was his way, he declined to waste those periods of forced repose and so took the opportunity to exercise and practice the skills that served him so well elsewhere in his life while sequestered in those littlest of rooms. To this end, over repeated visits to a particular water closet he began to observe that, while the cleanliness in general could not be faulted, there was one area which was reliably hygienic to a significantly lower standard than the rest. This region, populated by dust, tiny fragments of tissue, hair, and other detritus, he noted, was along the base of the wall directl...