diff --git a/main.tex b/main.tex
index d581b20..9942a00 100644
--- a/main.tex
+++ b/main.tex
@@ -31,7 +31,7 @@
 \usepackage{amsthm}
 \usepackage{comment}
 \usepackage{tikz}
-\usetikzlibrary{positioning}
+\usetikzlibrary{positioning,patterns,shapes}
 
 % theorems, definitions
 \newtheorem{theorem}{Theorem}[chapter]