Step 1: Gather materials
Also pictured are some work gloves and a set of pliers, which you may want if the fence sections are really dirty or in particularly bad shape. The pliers are handy for bending the wire.
Step 2: Prepare the fence sections
Next, fold the top of the small, inner loop on each section out one way and the larger loop the other way. You'll only need to go about 30 degrees in each direction for now.
Step 3: Assemble the tower!
I grabbed 18 sections of fence, so I could have built a 6-ring-high tower of 3-rings, but opted instead to build a 6-5-4-3 pyramid with a wide base. Assembling this structure was slightly more difficult than a simple tower, but the finished product serves the same purpose.