I knew that when resistors are put in parallel, they will have the same voltage going across them. So I designed a circuit that would do just that. Initially, I wanted to have four different color LEDs on the tree. However, no matter what I did only the yellow LED would light up. Then I remembered that different color LEDs have different resistances. Since electricity always follows the path of least resistance, each path of a parallel circuit MUST have the same level of resistance. After changing the bulbs to all be the same color, the circuit finally worked. Once the circuit was complete, I used the design of a foldable card to make it so when the card is closed, the tree would light up!