It belongs to a friend, the stem is square. Sorry for the blurry photo. I would appreciate it if I could get a name for her. Thanks in advance!
Here is a link that might be useful: Lamium maculatum 'Variegatum'
Hmmm....I'm not sure I agree...the teeth are more pointed in the OP photo....sharper and less crenated. You may be right but I hope I don't offend if I bump this to the top again.
Yes - the OP's picture probably shows Lamiastrum galeobdolon (formerly Lamium), an invasive species. If your friend is lucky it could be Lamiastrum 'Hermanns pride' which is a controllable clumper, so I'd keep a very close eye on the foliage as it develops and compare with pictures. But be ready with the spade.
Thank you, everyone! I *really* appreciate your help!