int l = 11;
int v = 15;
float i = 0;
void setup() {

pinMode(l,OUTPUT);
Serial.begin(9600);
}

void loop() {
for (i=0; i<270; i+=v){
analogWrite(l,i);
delay(100);
Serial.println(i);
}
for (i=255; i>0; i-=v) {
analogWrite(l,i);
delay(100);
Serial.println(i);
}
}