For a chain of 3 StarLights, you will need:
1 2xAA battery case
Battery Clip (PP3 clip)
15 3mm LEDs - 5 yellow, 5 red, 5 green
3 10ohm resistors
2.5m red wire
2.5m black wire
Step 1: Do the math, test the circuit...
V = 3 (supplied by battery) - 2.2 (forward voltage of LED) = 0.8
I = Combined current required by the LEDs = 0.02 x 5 = 0.1
0.8 / 0.1 = 8ohms of resistance
I tested the maths on the breadboard, and thankfully, it worked!