It took a while to find an actual article with art work created in the
cup as opposed to simply using lighter and darker coffee as water
I first found this image which I felt put me on the right track.
An image from an Italian coffee website:
search theory: Google images search engine keywords "coffee art"
Working from there and realizing "coffee art" pulled way too many
water color types artists, I went with a different search and found
what I hoped was the article, instead it was an ad for a book.
Gilkatho fine coffee supplies:
search theory: Google search engine keywords barista coffee art
Finally, a brainstorm, different words again but this time...GOLD!!!
I think this is the article you are referring to, It is an interview
with barista, Mark Christman.
Latte Art by Lura Lee:
search theory: Google search engine keywords article designs latte foam
This website also came up, altho it is more of a guide then an
article, it details how to make some of these wonderful designs.
Milk Frothing Guide - Latte Art Guide by Jim Schulman:
search theory: Google search engine keywords coffee milk art
Other interesting latte art sites:
Please feel free to ask for clarification before rating this answer.
Thanks and enjoy,