I poured a couple of drops of each of the following polishes on a zip-lock bag: RBL IKB:2012, China Glaze Dorothy Who?, GOSH Blue Ballon and...I really need to start writing notes on my swatches, I can't remember what the fourth polish is.
Then I took a needle and made spiraling patterns in the wet polish, let it dry for a couple of hours, and peeled the piece off. I then took my nail scissors and cut it in pieces that fit my nails - and lo and behold: Dry Water Marble nails ;)