And they can only be painted on with a left-handed paint brush....
Sorry to have to add to the fun but it's always odd to see questions on this forum that are asked in place of minimal CAR / Jepps / ICAO reading & research.
Chatted to a JAA certified TRE (Austrian) not too long ago about such questions asked in interviews or even line checks. He says that pilots flying into & out of international & often unfamiliar airports should appreciate the rwy standards, by way of markings, etc, it's certifications..... That was his argument anyway. (And yes, a "professional" pilot would've done the reading on the unfamiliar strip prior to the flight anyway).
Not knowing what certification standards & limits you're operating under can get you in trouble real quick, real bad. Eg: TERPS vs PANS OPS.