The OP edited his post to add an answer; according to the OP, it was a series called "Kutlas".
SOLVED - A friend of mine helped me found out the title! It's Kutlas, I suggest anyone interested to watch it. Definitely worth the time.
But it's not as easy to find even with that information, hence my answer.
This seems to be one or more episodes of CuttlasCuttlas, also known as El Bueno de Cuttlas‡, drawn by Calpurnio‡Calpurnio. "Kutlas" seems to be a transliteration, probably in Persian (the language on the page where I found it was identified as Persian by Chrome).
It features Cuttlas, who YouTube shows to be a semi-stick figure in all white, and his girlfriend Mabel, although she does not look like a letter M.
According to WikiPedia, it had a run as an animated series in the early nineties and has been shown on Comedy Central and Cartoon Network.
And there indeed is an episode with someone with a M-shaped body:
‡: Source in Spanish.