Total time to assemble: about 30 minutes.
Step 1: Materials
9 Volt battery
2 pairs of alligator clips
220 Ohm Resistor
Stripped copper wire (or paper clips)
Pliers (not needed, but helpful)
Sharp object, like a knife (not pictured, but hidden inside pliers/multi-tool)
Step 2: Poke some holes
Poke 4 holes wide enough for the wire to go through. These holes will be the height where your LEDs will sit. Make sure the holes are all at about the same height, and not too close that the wires will touch.
Mark +/- as to not get confused later on.
On the lid, poke 1 hole through the center.
Step 3: Ready the assembly
I took a plastic coated paper clip, and straightened it out.
Then, using the pliers, I went in about 1/2 inch and bent it 90 degrees.
At the other end of the paper clip, I made a small loop, placed the resistor in there, and gently closed it. The resistor will move, but not fall out.
On the resistor, I bent the leads coming out into hook shapes. These will catch the wires and close the circuit. We'll talk about in the next step.