I went through some old clothes I had at home and found an old shirt jacket that looks somewhat like a bicycle jacket. First I decided where to place the lights. So I took 6 yellow LED lights and poked them through the front layer of the jacket. I also poked 6 red LED lights in the back layer of the jacket.
Before I connected the lights with the wires, I made sure where to connect the negative and positive wires. I tried to connect one light to the battery source and it worked. I decided to stay with my original idea of creating a parallel circuit. Then I tried with two lights, sometimes only one light would turn on or they wouldn't turn on at all. There was a problem in the way the current was following from the batteries to the lights and back. To make sure that the wires didn't detach, I used electric tape to keep everything from moving.
Unfortunately at this point, the problem has nothing to do with the current or the battery, it is some of the lights that stopped working. That explains why not all the lights would light up or none of them would. So I had to keep detaching the wires and put in new lights. I noticed that two red lights in the back weren't working, now I had to use 4 lights instead of 6 lights. Even the all the yellow lights on one side stopped working but not the ones on the other side. I just had to get rid of those yellow lights that didn't work. I went through a lot of lights at this point so I just decided to leave the jacket the way it was.
I made two separate circuits for the red lights and the yellow lights, later attaching them together with clip wires. Then I used more clip wires to clip them to the new big circuit and a switch. Electric tape had to be used in order for the circuit to work when using the switch. On the first attempt to use the switch to power the circuit, it didn't work until I discovered that the electric tape wasn't sticking to the wire properly. The second attempt worked but only for half the circuit because of the electric tape detaching every time something would move. Also, the batteries should be taken out of the holder because somehow they are still hot even when the switch is off. This is obviously a fragile tool.
When I tested it out in the dark, I was happy that the lights were visible. The red ones shined brighter than the yellow ones though. Instead of putting a layer of material to keep everything together I decided not to because I wouldn't be able to demonstrate how it works in class. I took a picture of the lights shining in the dark just in case it doesn't work in class. I also took a video of how it looks like in the dark.