M is a variation of the Greek letter mu and the Semetic mem, which is also the Phoenician word for water. Originally M’s legs were uneven, perhaps resembling waves, which many scholars believe was a pictograph of water. In Greek mythology Cadmus, the founder of Thebes, introduced the Phoenician letters to the Greeks and is called the father of their alphabet. M is classified as a liquid in modern phoenetic definitiion. The jagged, uneven M of ancient times rounded in the uncial script, making it recognizable to the modern lower-case M.
A is the first letter of both the English and Roman alphabets, descended from the first letter of the Phoenician alphabet, adelp that was neither vowel or consonant. This letter represented the ox, which scholars have speculated was both a pictorial sign without any specific sound, and as a homage to the position of the sun at vernal equinox in the constellation Taurus.