diff --git a/4By4/4By4.ino b/4By4/4By4.ino
new file mode 100644
index 0000000..1ca12c3
--- /dev/null
+++ b/4By4/4By4.ino
@@ -0,0 +1,67 @@
+#include "TimerOne.h"
+#define TIME_PER_LAYER_IN_US 750
+#define ANODE_START_PIN 22
+#define CATHODE_START_PIN 8
+
+int LED_status[4] = {0}; // 16 bit * 4
+byte current_layer = 0;
+
+void setup() {
+    Serial.begin(115200);
+    Timer1.initialize();
+    Timer1.setPeriod(TIME_PER_LAYER_IN_US);
+    Timer1.attachInterrupt(drawOneLayer);
+    for (int i = 0; i < 16; i++) {
+        pinMode(ANODE_START_PIN + i, OUTPUT);
+    }
+
+    for (int i = 0; i < 4; i++) {
+        pinMode(CATHODE_START_PIN + i, OUTPUT);
+    }
+
+    randomSeed(analogRead(0));
+}
+
+void loop() {
+    // for (int i = 0; i < 4; i++) {
+    //     for (int j = 0; j < 16; j++) {
+    //         LED_status[i] ^= 1 << j;
+    //         delay(500);
+    //     }
+    // }
+
+    int count = 0;
+    while (count < 64) {
+        int num = random(64);
+        if ((LED_status[num / 16] >> (num % 16) ) & 1) {
+            continue;
+        }
+        LED_status[num / 16] ^= 1 << (num % 16);
+        delay(50);
+        count++;
+    }
+
+    delay(1000);
+
+    while (count > 0) {
+        int num = random(64);
+        if ((LED_status[num / 16] >> (num % 16) ) & 1) {
+            LED_status[num / 16] ^= 1 << (num % 16);
+            delay(50);
+            count--;
+        }
+    }
+
+    delay(1000);
+}
+
+void drawOneLayer() {
+    digitalWrite(CATHODE_START_PIN + current_layer, LOW);
+
+    current_layer = (current_layer + 1) % 4;
+    for (int j = 0; j < 16; j++) {
+        digitalWrite(ANODE_START_PIN + j, (LED_status[current_layer] >> j) & 1);
+    }
+
+    digitalWrite(CATHODE_START_PIN + current_layer, HIGH);
+}
\ No newline at end of file