I personally love this idea and whoever came up with it is genious!
Pour room temperature water into a disposable cup, almost to the top. Open all bottles of polish and place them within reach. Use at least three colors that have a bit of contrast. For example, use a pale shade, a dark shade and a medium shade.
Drop one or two drops of polish onto the surface of the water. The nail polish should spread out and make a circle on the water. If it drops to the bottom without creating a circle on the surface, try a different nail polish. This color is your base color for the marble effect, meaning it will show the most.
Drop one or two drops of your second color of nail polish on top of your base color. It should create a smaller circle on top of your base color.
Continue with each color that you would like to add to the effect. You can use many colors or you can use only two or three colors, repeating each color at least once in the same order.
Drag the tip of a cuticle stick through the circles of polish to create the marble effect. Begin at the center and drag the tip toward the outer edge. Reverse this for more swirls.
Insert your nail. The nail polish will adhere to your nail.
Remove nail from water. Remove tape or use nail polish remover and cotton swabs to clean up any excess polish. Repeat Steps 1 through 7 for each nail.
Apply top coat and let dry.