I just got done playing around with lesson 5 and changed it to have 10 LEDs. I am using pins 3 - 12 as outputs.
The thing is, some of the LEDs are dimmer than the others. It almost seems as though pin 3 is the brightest and pin 12 is the dimmest. Pins 9, 10, 11, 12 are noticeably dimmer than 3. I think the others are also dimmer, but they are not that different that it calls attention to them.
I have swapped the LEDs around and it doesn't matter. I have tried new resistors, and swapping them too. Same thing 3 brightest, 12 dimmest.
I thought it might be due to too many being on at once, but even when there is only 1 on at a time, the level of brightness is in correlation to it's pin position.
I have pictures of the setup, but I will have to post another one to show the dimm effect.
Thanks for the tutorial - it was awesome! I am going to use this in my Halloween robot costume.