I usedmodels own RED ALERT and FEELING BLUE and a Yellow called BUTTERCUP by gorge at asda :]
You need water, needle, cotton buds and some tape to limit the mess.
i used plasters on a roll but i have used electrical tape before.lol
I used a white base coat so that i gave the colours the best chance of being bright.
Now drag the needle quickly and smoothly through the varnish creating a pattern.
It will take a little while to get good at this but its fun.
(Sorry no picture of this step)
Now dip your finger in to the prettiest ared of the swirled varnish. leave you finger under the water and wait.
.. a few secs
Then use the cotton buds (q-tips) to gather up the varnish left on the water.