Question: do all cats have m's on their foreheads

Answer: No, A tabby is any domestic cat (Felis catus) that has a coat featuring distinctive stripes, dots, lines or swirling patterns, usually together with a mark resembling an 'M' on its forehead. Tabbies are sometimes erroneously assumed to be a cat breed. In fact, the tabby pattern is found in many breeds, and is a genetic landrace common among the general mixed-breed population. The tabby pattern is a naturally occurring feature that may be related to the coloration of the domestic cat's direct ancestor, the African wildcat (Felis lybica lybica), which--along with the European wildcat (Felis silvestris silvestris) and Asiatic wildcat (Felis lybica ornata)--has a similar coloration. A genetic study found five genetic clusters from tabbies to be ancestral to wildcats of various parts of the world.