I did this nail design a while ago, however I only remembered it now since I've been wearing the base colour as my go to polish for the last couple of weeks (XOX July).
Anyways, these nails remind me somewhat of art deco geometric designs, as do the colours. It's actually really simple to do, all you need are the following materials...
1. Various colour of nails polish
2. Make-up sponge (used for the middle finger)
3. Dotting tool (used for the ring finger - you can get a set off eBay HERE, great for other nail designs as well)
4. Nail striping tape (used for all the other fingers - got mine off eBay HERE, a range of colours you can use as actual designs)
And how do you use the striping tape? Paint your base colour, let it dry completely, place your striping tape in the lengths and positions you want, then paint over with your second/other colours, REMOVE THE TAPE as soon as you apply your second colour/s (you don;t want the tape to dry into your design!).
The sponging is self explanatory (literally dip the sponge in a puddle of polish and don't be too heavy handed when dabbing it on to your nail), as is the dotting tool (this way take a bit of practice). Et VOILA!