The Mool Mantar (or Mul Mantra) is the first ten words from the Sikh holy book, the Guru Granth Sahib. It is considered the most sacred composition in the religion.
The images above are from SikhiWiki. (great name!)
These handwriting samples, written by the holy gurus themselves, look quite different from the rigidity of most Gurmukhi typefaces. I have to do more comparing, but at first glance, it appears that extra-long, flowing “tails” were used to represent “u” vowels, rather than a subscript form, in some examples. And in some, dots, rather than short marks from the top bar, seem to represent the “aa” vowel stroke.
Ikoaŉkār saṯ nām karṯā purakẖ nirbẖao nirvair akāl mūraṯ ajūnī saibẖaŉ gur parsāḏ.