diff --git a/src/midterm_presentation/main.tex b/src/midterm_presentation/main.tex
index eb093b8..264bced 100644
--- a/src/midterm_presentation/main.tex
+++ b/src/midterm_presentation/main.tex
@@ -27,7 +27,7 @@
 \usetikzlibrary{spy, external, intersections, positioning}
 
 % \ifdefined\ishandout\else
-% \tikzexternalize
+\tikzexternalize
 % \fi
 
 \usepackage{pgfplots}
@@ -182,9 +182,9 @@
         \item Quantum computers represent information through
             correlations of qubits, not their values \\
             directly \citereference{preskill_quantum_2018}
-        \item We want to not disturb the quantum state but need to
-            interact with the system $\rightarrow$ Protect the state
-            with \ac{qec}
+        \item Errors during quantum computation are inevitable
+            because quantum systems are fragile
+        \item We want to interact with the quantum state but not disturb it
         \item We employ more physical qubits to introduce
             redundancy and use the resulting \emph{physical} state to
             represent the \emph{logical} state
@@ -243,8 +243,8 @@
     %   much"
 
     \begin{itemize}
-        \item As mentioned earlier, \ac{qec} is actually able to
-            protect the quantum state with all its correlations
+        \item \Ac{qec} is actually able to protect the quantum state
+            with all its correlations
         \item We have to consider phase flip errors in addition to
             bit flip errors \citereference{roffe_quantum_2019}
             \vspace*{-10mm}
@@ -345,13 +345,17 @@
     \begin{itemize}
         \item We entangle the state with \emph{ancilla qubits} to
             perform syndrome measurements \citereference{nielsen_quantum_2010}
+        \item \red{Implicitly introduce the concept of a quantum gate
+            by mentioning CNOT gates?}
+        \item \red{Mention that we can perform syndrome extraction
+            with just CNOTs and H? (and find citation)}
+        \item \red{Do I need to show what the syndrome extraction
+            circuitry for Z errors looks like?}
         \item Example: The 3-qubit repetition code%
             \footnote {
                 Note that, for simplicity, this chosen example is a
-                code that is not only able to correct X errors (bit flips)
+                code that is only able to correct X errors (bit flips)
             } %
-            \red{Do I need to show what the syndrome extraction
-            circuitry for Z errors looks like?}
     \end{itemize}
 
     \vspace*{-10mm}
@@ -372,7 +376,7 @@
             % tex-fmt: off
             \Qcircuit @C=1em @R=.7em {
                                      & & \ctrl{3} & \qw      & \qw      & \qw      & \qw    & \qw \\
-                \ket{\psi}_\text{L}  & & \qw      & \ctrl{2} & \ctrl{3} & \qw      & \qw    & \qw \\
+                \ket{\psi}           & & \qw      & \ctrl{2} & \ctrl{3} & \qw      & \qw    & \qw \\
                                      & & \qw      & \qw      & \qw      & \ctrl{2} & \qw    & \qw \\
                 \ket{0}_{\text{A}_1} & & \targ    & \targ    & \qw      & \qw      & \meter &     \\
                 \ket{0}_{\text{A}_2} & & \qw      & \qw      & \targ    & \targ    & \meter &
@@ -391,7 +395,6 @@
     \addreferences
     {nielsen_quantum_2010}
     \stopreferences
-
 \end{frame}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -405,23 +408,54 @@
 \begin{frame}
     \frametitle{Fault Tolerance}
 
+    \vspace*{-18mm}
+
     \begin{itemize}
-        \item Quantum gates are faulty $\rightarrow$ we need QEC \\
-            But we do QEC with faulty gates $\rightarrow$ we need
-            fault tolerant QEC %
-            \footnote{
-                Designing fault-tolerant circuits using detector
-                error models - Gong et al, Section 4.1
-            }
-        \item We generally do multiple rounds of syndrome extraction
-        \item The Threshold theorem
-            \setcounter{footnote}{0}
-        \item Definition of fault tolerance \footnotemark
-        \item \red{Different approaches to fault tolerance?}
+        \item The quantum gates we use for syndrome extraction are
+            faulty themselves \\
+            $\rightarrow$ We need \emph{fault-tolerant} \ac{qec}
+            \citereference{roffe_quantum_2019}
+        \item A \ac{qec} procedure is said to be fault tolerant if it
+            can account for errors that occur at any location in the circuit
+        \item We have to modify the syndrome extraction circuitry to
+            be fault tolerant (e.g., by using specially prepared
+                multi-qubit states for each ancilla
+            \citereference{shor_fault-tolerant_1997})
+        \item We generally perform multiple rounds of syndrome extraction
     \end{itemize}
+
+    \vspace*{-3mm}
+
+    \begin{figure}[H]
+        \centering
+        \scalebox{0.6}{
+            \mbox{
+                % tex-fmt: off
+                \Qcircuit @C=1em @R=.7em {
+                                         & & \ctrl{3} & \qw      & \qw      & \qw      & \qw                  & \qw & \ctrl{5} & \qw      & \qw      & \qw      & \qw    & \qw \\
+                    \ket{\psi}           & & \qw      & \ctrl{2} & \ctrl{3} & \qw      & \qw                  & \qw & \qw      & \ctrl{4} & \ctrl{5} & \qw      & \qw    & \qw \\
+                                         & & \qw      & \qw      & \qw      & \ctrl{2} & \qw                  & \qw & \qw      & \qw      & \qw      & \ctrl{4} & \qw    & \qw \\
+                    \ket{0}_{\text{A}_1} & & \targ    & \targ    & \qw      & \qw      & \meter               &     &          &          &          &          &        &     \\
+                    \ket{0}_{\text{A}_2} & & \qw      & \qw      & \targ    & \targ    & \meter               &     &          &          &          &          &        &     \\
+                                         & &          &          &          &          & \ket{0}_{\text{A}_3} &     & \targ    & \targ    & \qw      & \qw      & \meter &     \\
+                                         & &          &          &          &          & \ket{0}_{\text{A}_4} &     & \qw      & \qw      & \targ    & \targ    & \meter &     & \cdots
+                }
+                % tex-fmt: on
+            }
+        }
+
+        \caption{Multiple rounds of syndrome measurements for the
+        3-qubit repetition code}
+    \end{figure}
+
+    % \vspace*{-2mm}
+
+    \addreferences
+    {roffe_quantum_2019}
+    {shor_fault-tolerant_1997}
+    \stopreferences
 \end{frame}
 
-% TODO: Where to we introduces the different kinds of noise models?
 \begin{frame}
     \frametitle{Noise models}