Step 1.
Start off by making a new document that's 700 x 700 and fill it with: #1D6FA8
Step 2.
Next create a new layer, and while using the polygon lasso tool, make a selection like this:
Step 3.
Fill the selection with a color that is slightly lighter than your background, I've used: #3295DA.
After this you press Ctrl+D to deselect the area.
Step 4.
Next duplicate this layer. and go to Edit->Transform->Flip vertically.
Go ahead and press 'V' on the keyboard to get out the Move Tool, and position the new flipped version like so:
Step 5.
Try to line up the tips as close as possible:
Step 6.
Press Ctrl + E to merge these two layers into one and duplicate it again. Once the layer has been duplicated press Ctrl + T on your keyboard to bring up the free transform tool. place the cursor just over the top right corner of the square, and rotate the shape like so: Press return on your keyboard to finalize the rotation
Step 7.
Here's the fun part...
Press Ctrl+Shift+Alt+T all at the same time on your keyboard. This will repeat the last transformation.... which will rotate the shape the exact amount that we need.
Step 8.
Continue pressing Ctrl+Shift+Alt+T until you've nearly completed the background:
Step 9.
If you want to add a little depth you can go ahead and merge all the layers together (except the background layer) and add a slight inner glow with black... here's the settings I've used:
Step 10.
Another option is to go to Filter->Distort->Twirl and you'll get interesting effects with that as well:
More Tutorials: 
