How to make The Internet (from The IT Crowd).

Step 5 Containment & Completion

Now, with the circuit complete (ish), there it one last thing to do. We need to attach those output wires to the LED (which we put in place in step 3).
I just soldered the ends of the wires straight onto the legs of the LED. Not the most resilient connection, but with everything in the box, they shouldn't be under much strain anyways.
I used only white wire for two reasons. Firstly, to make it harder for you guys. Secondly, because I'm cheap, and only wanted to buy one colour wire.

The wire coming from leg 3 of the 555 IC goes to the positive leg of the LED, and the other wire goes from the resistor to the negative leg of the LED (aren't we glad we identified the negative leg now?).
I used a small piece of tape to secure the circuit to the board. It's a small, light circuit, and the box should be undergoing massive g-forces so this should be fine.

And now, your circuitry should be complete. If you insert the batteries now your LED should be flashing. If not, you're a naughty person and you've done something wrong. Now go and think about what you've done.
Or you can try turning it on and off again.

Now, close up the box! If you feel the need to, you can use the screws provided (in a small bag inside the box), but I haven't bothered thus far as friction seems to be enough and I'd like easy access if the battery dies. At this stage you can also appreciate why curling the wires for the LED helps. Otherwise you'd either have too little slack presenting a risk to the LED connections when opening/closing the lid, or too much slack getting in the way when closing the lid.