No, you can parallel wire it, so it ends up only having one cord.

Start with one cord like normal, solder it to the first piece of flexwatt, then run both pieces of cord(as long as your shelves are tall, plus some) to the second piece of flexwatt, where you will then use two more pieces of wire, twist the copper parts together and solder both wires to the flexwatt. Do that as many times as you need to, then end it with the male part of the cord.

I'm probably making it sound confusing, but it's very easy. Lemme find a diagram for ya!

http://www.mgreptiles.com/files/wiring_in_parellel.pdf

Poor BeanFarm's links are broken...