I start in “up” and end in “under,”
A vowel that echoes like distant thunder.
In “unique” and “unicorn,” I play my part,
A letter of mystery and an enigmatic start.

I am slender and lean, a graceful sight,
A corner turned just right.
A straight line with a swift bend,
In scripts ancient, I transcend.
What am I, in form and hue,
A letter’s shape that’s tried and true?