diff --git a/exp0-blinking-led/blinking-led.ino b/exp0-blinking-led/blinking-led.ino
new file mode 100644
index 0000000..591402f
--- /dev/null
+++ b/exp0-blinking-led/blinking-led.ino
@@ -0,0 +1,49 @@
+/**
+ * @file blinking-led.ino
+ *
+ * This is free and unencumbered software released into the public domain.
+ * Anyone is free to copy, modify, publish, use, compile, sell, or
+ * distribute this software, either in source code form or as a compiled
+ * binary, for any purpose, commercial or non-commercial, and by any
+ * means.
+ *
+ * In jurisdictions that recognize copyright laws, the author or authors
+ * of this software dedicate any and all copyright interest in the
+ * software to the public domain. We make this dedication for the benefit
+ * of the public at large and to the detriment of our heirs and
+ * successors. We intend this dedication to be an overt act of
+ * relinquishment in perpetuity of all present and future rights to this
+ * software under copyright law.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * For more information, please refer to <http://unlicense.org/>
+ */
+
+/*
+ * The pin # of the LED we are going to use.
+ */
+#define LED_PIN 13
+
+/*
+ * 1-time setup code that runs during initialization.
+ */
+void setup(void) {
+  pinMode(LED_PIN, OUTPUT);
+}
+
+/*
+ * Main code, which will run forever.
+ */
+void loopvoid() {
+digitalWrite(LED_PIN, HIGH);
+delay(1000);
+digitalWrite(LED_PIN, LOW);
+delay(1000);
+}
diff --git a/exp0-blinking-led/notes.org b/exp0-blinking-led/notes.org
new file mode 100644
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+++ b/exp0-blinking-led/notes.org
@@ -0,0 +1,5 @@
+* Extensions
+- Can you change the PIN in the code and figure out how to still get the LED to blink?
+- Can you make 2 LEDs blink at the same time from a single pin?
+- Can you make 2 LEDs blink at the same time from two different pins?
+- Can you make 2 LEDs blink alternatively?
diff --git a/libraries/readme.txt b/libraries/readme.txt
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index 0000000..96ce674
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+++ b/libraries/readme.txt
@@ -0,0 +1 @@
+For information on installing libraries, see: http://www.arduino.cc/en/Guide/Libraries