The following codes were written by Code::Blocks v.12.11, but you can use any editor of your choice. 
Create two separate files, one named Pixel.h, the other named Pixel.cpp. Create a new folder named "Pixel" under "libraries" directory and put both Pixel.cpp and Pixel.h in there. Learn more about Arduino libraries: [[http://arduino.cc/en/Guide/Libraries]]


**Pixel.h**
<code>
/* First Release April 11, 2013 by Jenna Yun Lee, Cooper Union, All rights reserved.
I strongly support open source programming. Free to distribute and modify,
but please keep the original copyright information.
Contact lee55@cooper.edu for suggestions/errors/helps!

This code is originally written for a two-player arcade game that makes uses of LED lights.
Pixel.h and Pixel.cpp allows a programmer to control each pixel from an array of LEDs much easily.
*/

//Arduino Setting; Each arduino has different chipset per version.
//Include the following if commands for program expandability.

#if (ARDUINO >= 100)
 #include <Arduino.h>
#else
 #include <WProgram.h>
 #include <pins_arduino.h>
#endif


#define PIXEL_H

class Pixel
{
    //Constructor
    public:
        Pixel();
        Pixel(int address);
      void
        setAddress(int new_address),    //Change address
        setSide(bool new_side),     //Changes side
        setState(bool new_state),   //Change state; 1 if the target is hit, 0 otherwise. 0 by default.
        setColor(int new_color_r, int new_color_g, int new_color_b);    //Changes color
      int
        getAddress(void),
        getRed(void),
        getGreen(void),
        getBlue(void);
      bool
        getSide(void),
        getState(void);

    private:
        int
            address, // address number in decimals
            color_r,
            color_g,
            color_b;
        bool
         side, //0 for RED, 1 for BLUE
         state; //0 for off, 1 for on
};
</code>

**Pixel.cpp**

<code>
/* First Release April 11, 2013 by Jenna Yun Lee, Cooper Union, All rights reserved.
I strongly support open source programming. Free to distribute and modify,
but please keep the original copyright information.
Contact lee55@cooper.edu for suggestions/errors/helps!

This code is originally written for a two-player arcade game that makes uses of LED lights.
Pixel.h and Pixel.cpp allows a programmer to control each pixel from an array of LEDs much easily.
*/

#include "Pixel.h"
//Constructors
Pixel::Pixel() {}

Pixel::Pixel(int addr)
{
    address = addr;
    state = 0;
    //Our arcade game uses 5x5 LED grid, so 50 flippers for two sides.
    //Side 0 if address number is less than 24 (up to 25th LED), Side 1 otherwise
    if (addr>24) side = 1;
    else side =0;
}

//A series of getter-setter functions from here:

//Address
int Pixel::getAddress(void) {
    return address;
}
void Pixel::setAddress(int new_address) {
    address = new_address;
}

//Side
bool Pixel::getSide(void) {
    return side;
}
void Pixel::setSide(bool new_side){
    side = new_side;
}

//State
bool Pixel::getState(void){
     return state;
}
void Pixel::setState(bool new_state){
      state = new_state;
}

//Color, RGB separately
int Pixel::getRed(void) {
    return color_r;
}
int Pixel::getGreen(void) {
    return color_g;
}
int Pixel::getBlue(void) {
    return color_b;
}
void Pixel::setColor(int new_color_r, int new_color_g, int new_color_b) {
    color_r = new_color_r;
    color_g = new_color_g;
    color_b = new_color_b;
}
</code>