Making Arduino HelloWorld a smidge more interesting

arduino/HelloWorld/HelloWorld.ino

@@ -1,5 +1,6 @@
 const unsigned int LED_PIN = 13;
 const unsigned int PAUSE = 500;
+const unsigned int FLASH_DURATION = 50;
 
 
 void setup() {
@@ -8,8 +9,19 @@ void setup() {
 
 
 void loop() {
-    digitalWrite(LED_PIN, HIGH);
+  for (int i = 1; i < 4; i++) {
+    flash(i);
     delay(PAUSE);
-    digitalWrite(LED_PIN, LOW);
+  }
   delay(PAUSE);
 }
+
+
+void flash(int n) {
+  for (int i = 0; i < n; i++) {
+    digitalWrite(LED_PIN, HIGH);
+    delay(FLASH_DURATION);
+    digitalWrite(LED_PIN, LOW);
+    delay(FLASH_DURATION);
+  }
+}