int potpin = A0;
int potVal = 0;


int redpin =11;
int grnpin =10;
int blupin = 9;

//program variables
int redVal = 0;
int grnVal = 0;
int bluVal = 0;

void setup() {
  // put your setup code here, to run once:
pinMode(redpin, OUTPUT);
pinMode(grnpin, OUTPUT);
pinMode(blupin, OUTPUT);

}
//Main program
void loop() {
  // put your main code here, to run repeatedly:
potVal = analogRead(potpin);
if (potVal < 341)
{
  potVal = (potVal*3)/4;
  redVal = 256-potVal;
  grnVal = potVal;
  bluVal = 1;

}
else if (potVal <682);

{
  redVal = 1;
  grnVal = 256-potVal;
  bluVal = potVal;

}
else //Upper third of potentiometer's range(682-1023) 
{
  potVal = ((potVal-683)*3)/4;
  redVal = potVal;
  grnVal = 1;
  bluVal = 256-potVal;
}
analogWrite(redpin, redVal);
analogWrite(grnpin, grnVal);
analogWrite(blupin, bluVal);

}