diff --git a/ShiftRegLeds/lessons/lesson42.cpp b/ShiftRegLeds/lessons/lesson42.cpp
new file mode 100644
index 0000000..e4c2c43
--- /dev/null
+++ b/ShiftRegLeds/lessons/lesson42.cpp
@@ -0,0 +1,34 @@
+// https://www.youtube.com/watch?v=n3qmQHzcgto&list=PLGs0VKk2DiYw-L-RibttcvK-WBZm8WLEP&index=42
+
+#include <Arduino.h>
+
+int latchPin = 11;
+int clockPin = 9;
+int dataPin = 12;
+
+int dt = 2500;
+byte LED1s = 0b10101010;
+byte LED2s = 0b01010101;
+
+
+void setup() {
+  // put your setup code here, to run once:
+  Serial.begin(9600);
+  pinMode(latchPin, OUTPUT);
+  pinMode(clockPin, OUTPUT);
+  pinMode(dataPin, OUTPUT);
+
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+  digitalWrite(latchPin, LOW);
+  shiftOut(dataPin, clockPin, LSBFIRST, LED1s);
+  digitalWrite(latchPin, HIGH);
+  delay(dt);
+
+  digitalWrite(latchPin, LOW);
+  shiftOut(dataPin, clockPin, LSBFIRST, LED2s);
+  digitalWrite(latchPin, HIGH);
+  delay(dt);
+}
diff --git a/ShiftRegLeds/src/main.cpp b/ShiftRegLeds/src/main.cpp
index e4c2c43..a42fc76 100644
--- a/ShiftRegLeds/src/main.cpp
+++ b/ShiftRegLeds/src/main.cpp
@@ -1,4 +1,4 @@
-// https://www.youtube.com/watch?v=n3qmQHzcgto&list=PLGs0VKk2DiYw-L-RibttcvK-WBZm8WLEP&index=42
+// https://www.youtube.com/watch?v=FwiKHHUbuLI&list=PLGs0VKk2DiYw-L-RibttcvK-WBZm8WLEP&index=43
 
 #include <Arduino.h>
 
@@ -6,8 +6,8 @@ int latchPin = 11;
 int clockPin = 9;
 int dataPin = 12;
 
-int dt = 2500;
-byte LED1s = 0b10101010;
+int dt = 25;
+byte LED1s = 0b00000000;
 byte LED2s = 0b01010101;
 
 
@@ -27,8 +27,11 @@ void loop() {
   digitalWrite(latchPin, HIGH);
   delay(dt);
 
-  digitalWrite(latchPin, LOW);
-  shiftOut(dataPin, clockPin, LSBFIRST, LED2s);
-  digitalWrite(latchPin, HIGH);
-  delay(dt);
+  Serial.println(LED1s, BIN);
+  LED1s++;
+
+  // digitalWrite(latchPin, LOW);
+  // shiftOut(dataPin, clockPin, LSBFIRST, LED2s);
+  // digitalWrite(latchPin, HIGH);
+  // delay(dt);
 }