diff --git a/week2/main.ino b/week2/week2.ino
similarity index 100%
rename from week2/main.ino
rename to week2/week2.ino
diff --git a/week3/week3.ino b/week3/week3.ino
new file mode 100644
index 0000000..4051901
--- /dev/null
+++ b/week3/week3.ino
@@ -0,0 +1,21 @@
+void setup() {
+	pinMode(0, OUTPUT);
+	pinMode(1, OUTPUT);
+	analogReadResolution(8);
+}
+
+void loop() {
+	int light = random(0, 2);
+	delay(1000);
+	digitalWrite(light, HIGH);
+	delay(1000);
+	digitalWrite(light, LOW);
+	while (analogRead(A0) < 240 && analogRead(A1) < 240);
+	int correct = (analogRead(A0) < 128) ^ light;
+	for (int i = 0; i < 4; ++i) {
+		digitalWrite(correct, HIGH);
+		delay(200);
+		digitalWrite(correct, LOW);
+		delay(200);
+	}
+}