This for loop will cycle infinitely. How do I make it cycle from low to high and back to low a single time?

int timer = 100; // The higher the number, the slower the timing.

void setup() { // use a for loop to initialize each pin as an output: for (int thisPin = 2; thisPin < 8; thisPin++) { pinMode(thisPin, OUTPUT); } }

void loop() { // loop from the lowest pin to the highest: for (int thisPin = 2; thisPin < 8; thisPin++) { //increment // turn the pin on: digitalWrite(thisPin, HIGH); delay(timer); // turn the pin off: digitalWrite(thisPin, LOW); }

// loop from the highest pin to the lowest: for (int thisPin = 7; thisPin >= 2; thisPin--) { //decrement // turn the pin on: digitalWrite(thisPin, HIGH); delay(timer); // turn the pin off: digitalWrite(thisPin, LOW); } }