I have been trying my best to track the "career" of this individual. I first saw his graffiti on the LRT posts in Caloocan. He did sound like a former teacher on the loose, trying to teach passers-by a thing or two about stuff we don't normally take notice of. Unfortunately, I didn't have a camera back then. Some years back, more of his graffiti appeared on the posts of the MRT along EDSA.
This one I saw on a post of an abandoned building along Avenida Rizal. I wonder who the guy doing all these is!