//
// tri-color LED *common cathode*
//  

int ledpin1 = 2;                           // red LED connected to pin 2 via 1K ohm resistor
int ledpin2 = 3;                           // blue LED connected to pin 3 via 1K ohm resistor
int ledpin3 = 4;                           // green LED connected to pin 4 via 1K ohm resistor
                                           // LED cathode connected to ground
void setup() 
{ 
  // nothing for setup 
} 
 
void loop() 
{ 
  
  //+++++++++
  // turn on and off red LED
  //+++++++++
 
    analogWrite(ledpin1, 255);               // turn on the voltage on pin 2 to 5 volts
    delay(500);                              // wait for 500 milli seconds 
         
    analogWrite(ledpin1, 0);                 // turn off the voltage on pin 2 to 0 volts 
    delay(500);                              // wait for 500 milli seconds 
                             
   
   //+++++++++
   // turn on and off blue LED
   //+++++++++
  
    analogWrite(ledpin2, 255);                 // turn on the voltage on pin 3 to 5 volts
    delay(500);                              // wait for 500 milli seconds 
         
    analogWrite(ledpin2, 0);                 // turn off the voltage on pin 3 to 0 volts 
    delay(500);                              // wait for 500 milli seconds 
                             
   
  
   
   //+++++++++
   // turn on and off green LED
   //+++++++++
   
    analogWrite(ledpin3, 255);                 // turn on the voltage on pin 4 to 5 volts
    delay(500);                              // wait for 500 milli seconds 
         
    analogWrite(ledpin3, 0);                 // turn off the voltage on pin 4 to 0 volts 
    delay(500);                              // wait for 500 milli seconds 
                             
    
}