This is my basic attempt to recreate the look somewhat without going to a salon to get them airbrushed.
Base color (painted on): OPI's Fiercely Fiona
Top Right: OPI's Rumples Wiggin'
Bottom Right: OPI's What's With the Cattitude?Bottom Left: China Glaze's Something Sweet
The three colors other than the base color were sponged on with a cosmetic sponge. Just paint the sponge (you may want to cut it to get a wedge shape if it's not already) and apply to the nail. It may take a few coats to get the tone of the color you want.
Let me warn you, clean up takes a lot of time if you're as messy as me. Pretty much my entire finger was covered in polish up to the first joint. You may want to cover exposed skin in tape so you can just peel off most of the mess instead of spending eleven 12-minute Metalocalypse episodes trying to rub off the polish like I did.
Overall, I like the look! Normally, I use super-blunt straight edges so this is a nice change. It's also super easy to do because mistakes are hard to come by, and if you do mess up it can be fixed easily.
Please excuse the new nail shape, it's an experiment in vintage pointyness.
Two thirds of the nail is China Glaze's Shower Together (teal) over one third of Barielle's U-Concrete-Me (gray), separated by silver stripping tape.
I freehanded the teal over the gray. The line separating the colors doesn't have to be extremely perfect because the stripping tape covers any small mishaps. If you don't think you'll be able to freehand the edge, wait until your base color is completely dry and place a piece of tape over the part of the nail you don't want covered. Wait about a minute and peel the tape off leaning toward/in the direction of the wet polish (the polish should still be more wet than dry). This allows the polish to form a smooth edge that's more flush with the nail instead of a leaving a rough edge where the polish would have butted up against the tape.
Let me say, for the record, that Shower Together is one of my least favorite colors that I own (it was also my very first China Glaze), but I absolutely adore this color paired with gray. Currently my toes are a gray based leopard with teal spots/black edges annnddd it's gorgeous. It's a nice fall/winterish color combo.