Hello! Just a quick point for working with LEDs. I just used a IC named 74HC595 and it's fun! you use 3 I/O pins and you can control up to 8 LEDs...saves you some space! ( just learned this from my r3 kit )
Pssssssst, ei, don't tell anyone else about this – google: "MCP23017".
You can control 16 LED's at the same time and 128 by multiplexing or listen for up to 240 buttons by multiplexing with only 2 pins, and you can connect up to 8 of them to those same 2 pins to control 128 LED's at one time, multiplex 8192 or listen for up to 16256 buttons.
This is a huge secret, I can get banned for saying this so don't tell anyone 
3Dgeo:
This is a huge secret, I can get banned for saying this so don't tell anyone
You're out of the club, Dude! Turn in all of your voids by sundown.
boolrules:
Turn in all of your voids by sundown.
Including void setup() and void loop()!
Noooo, please, not like this, I didn't snitch the important stuff – about 2 wire I2C comunication, multiplexing or even about addressable LED like WS2812B which needs only 1 pin to control unlimited number of them.
Have mercy!!!