the م letter stays the same at the end of the word like قلم - pen لوم - blame نوم - sleep it's form changes in the middle and the beginning of the word it's form in the beginning is مـ like a circle with a line attatched to it in the middle ـمـ like a circle between two lines some words: محطة - station محمول - mobile مجهول - unknown

the form of the letter change depends on it's place maybe because it is the last character of the word see this : all the letter forms https://sites.google.com/a/elmajd.tzafonet.org.il/class-1b/53-1 م forms http://i.ytimg.com/vi/CPzty6WB_Lg/maxresdefault.jpg