diff --git a/examples/hamiltonian-learning-periodic/hamiltonian-learning-periodic.py b/examples/hamiltonian-learning-periodic/hamiltonian-learning-periodic.py
index e74c9ee1..a43f9328 100644
--- a/examples/hamiltonian-learning-periodic/hamiltonian-learning-periodic.py
+++ b/examples/hamiltonian-learning-periodic/hamiltonian-learning-periodic.py
@@ -49,13 +49,13 @@
 
 # %%
 # Step 0: Get Data and Prepare Data Set
-# =====================================
+# -------------------------------------
 #
 
 
 # %%
 # Download Data
-# -------------
+# ~~~~~~~~~~~~~
 #
 
 filename = "data.zip"
@@ -75,7 +75,7 @@
 
 # %%
 # Load structures and DFT data
-# ----------------------------
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 #
 
 # %%
@@ -144,7 +144,7 @@ def update(frame):
 
 # %%
 # Instantiate machine learning data set
-# -------------------------------------
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 #
 
 
@@ -233,7 +233,7 @@ def update(frame):
 # %%
 # Step 1: Build a machine learning model for the electronic Hamiltonian of
 # graphene in a minimal basis
-# ====================================================================================================
+# --------------------------------------------------------------------------------
 #
 
 
@@ -319,7 +319,7 @@ def update(frame):
 
 # %%
 # Set up the training loop
-# ------------------------
+# ~~~~~~~~~~~~~~~~~~~~~~~~
 #
 
 
@@ -360,7 +360,7 @@ def update(frame):
 
 # %%
 # Evaluate model accuracy
-# =======================
+# -----------------------
 #
 
 
@@ -449,7 +449,7 @@ def update(frame):
 
 # %%
 # Graphene band structure
-# -----------------------
+# ~~~~~~~~~~~~~~~~~~~~~~~
 #