Drawing a Quatrefoil

At first glance, this design looks like it should be an easy one. After all, putting four circles together seems straightforward enough. But, as it turns out there's a catch. If you make the circle's border too thin or too thick, the design just doesn't work. Fortunately, I have a few solutions to help you get that right. Firstly, if you're working on a computer, go use this tutorial to make things super easy. Alternatively, you can try using a grid to make this design:

An example of making a quatrefoil using a grid

Don't have a grid handy? Here's how to make this symbol by hand:
Start off by drawing a very large plus.
Draw lines from the center of each arm until they meet, forming a big square.
Now, what you've really done is make a set of four connected pluses. Mark off the last fourth of each arm on the top plus.
Continue on by adding similar marks to the other three pluses.
Now that the layout is done, use the marks and the ends of the pluses to guide you in making the eight circles making up the quatrefoil.
Erase the area marked in green.
Tidy things up a tad and your quatrefoil is complete!