I wanted to try needle marbling, because I thought it might enable me to do some abstract swirly thing. But that didn't really work the way I'd envisioned it, so it became an abstract splattery thing! I actually like the results. They have kind of a Rainbow Fish vibe.
So using a good quarter of my blue collection and a needle:
I came up with this:
The light blue was H&M Deep Sea, and the shiny one is Sinful Colors Aqua. The nail polishes knew I was going for an ocean vibe!