void setup() {
  // put your setup code here, to run once:
pinMode(6,OUTPUT);
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:

for(int i=0;i<256;i++)
{
  analogWrite(6,i);
}

for(int i=255;i>=0;i--)
{
  analogWrite(6,i);
}


}