Beautiful model, Warmuncher. Perhaps the following info will be helpful to those of you planning to home-brew your own circuits:
Electrical Engineering 101:
A current limiting resistor is required to be wired in series with each LED. If you don't use one, you will instantly burn out the LED as well as short-circuit your power supply. To calculate the value of this current limiting resistor, you need to know the rated current of the LED you are using, it's usually on the package.
Then simply use Ohm's Law:
E=IR
Where E is voltage of your source
I is the current rating in amps of your LED (if given in milliamps, divide by 1000 to get amps)
and R is the value of the resistor in Ohms.
Rearranging Ohm's law to find resistance, the formula is
R= E / I
(I have found that for most applications, the resistance value works out to be about 470 ohms.)
For the POWER RATING of the resistor, usually 1/2 watt is way more than enough.