Thankfully, as I have quite the arsenal of nail polish colours, I didn't need to buy any new colours to fulfil this, instead drawing on supplies from existing reserves:
Colours: Rimmel London in Green Grass, Missguided Mislead (free with magazine years ago) and The Works topcoat
I painted four nails yellow, with the ring finger green:
I'm undecided about this. As you can see, the Missguided nail polish has sparkles in it, where the green is just a solid block of colour. I actually have Rimmel London in a similar shade to the yellow, but just without sparkles, and I figure I probably should have gone for continuity.
Oh well, what's done is done, I ain't removing it! :p