Just an FYI, I have found some CA (super glue) products will react with permanent felt tip on foam flies and turn it red. I have not experimented with different colors I think it was a slider I had "painted" yellow with a Sharpie that turned red when it came into contact with the CA.
If Coach cover that I apologize, I have only skimmed the article and copied the jokes.
The inherent vice of capitalism is the unequal sharing of blessings; the inherent virtue of socialism is the equal sharing of miseries. Winston Churchill