It's funny to learn there's a term for this. It reminds me of something that happened in our church parking lot a couple of years ago. Someone (presumably a neighbourhood kid) had drawn a big black phallus on the nice white-ish concrete path. It was there for a few weeks, so I decided to get some turpentine and a scrubbing brush and clean it off. However, I scrubbed it so well that after I'd finished there was big white phallus (much whiter than the surrounding path). The white phallus remains to this day, though it is fading.