diff --git a/examples/lessons/01/index.html b/examples/lessons/01/index.html
index 3ed121903..560663817 100644
--- a/examples/lessons/01/index.html
+++ b/examples/lessons/01/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/02/index.html b/examples/lessons/02/index.html
index 6445155f7..91338a07d 100644
--- a/examples/lessons/02/index.html
+++ b/examples/lessons/02/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/03/index.html b/examples/lessons/03/index.html
index 1292f9bf4..ace4eb9e2 100644
--- a/examples/lessons/03/index.html
+++ b/examples/lessons/03/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/04/index.html b/examples/lessons/04/index.html
index 48ff3c1cb..6eca9a5c1 100644
--- a/examples/lessons/04/index.html
+++ b/examples/lessons/04/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/05/index.html b/examples/lessons/05/index.html
index c59d9f541..4733676f3 100644
--- a/examples/lessons/05/index.html
+++ b/examples/lessons/05/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/06/index.html b/examples/lessons/06/index.html
index 2533f7261..c0c89ac21 100644
--- a/examples/lessons/06/index.html
+++ b/examples/lessons/06/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/07/index.html b/examples/lessons/07/index.html
index e666f1608..511bb5392 100644
--- a/examples/lessons/07/index.html
+++ b/examples/lessons/07/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/08/index.html b/examples/lessons/08/index.html
index fe99b0738..08a09e1ea 100644
--- a/examples/lessons/08/index.html
+++ b/examples/lessons/08/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/09/index.html b/examples/lessons/09/index.html
index bd26b8fb2..f31a38f68 100644
--- a/examples/lessons/09/index.html
+++ b/examples/lessons/09/index.html
@@ -15,7 +15,7 @@
- a
+
diff --git a/examples/lessons/16/index.html b/examples/lessons/16/index.html
index baf0510a4..9db1d1572 100644
--- a/examples/lessons/16/index.html
+++ b/examples/lessons/16/index.html
@@ -15,7 +15,7 @@
- a
+