diff --git a/slides/sections/4.md b/slides/sections/4.md
index 198db64..f3a1c97 100644
--- a/slides/sections/4.md
+++ b/slides/sections/4.md
@@ -185,7 +185,7 @@ $$
     \draw <6> [domain=-0.1:2.9, smooth, variable=\x, cyclamen, very thick]
                plot ({\x}, {exp(-(\x - 1.4)*(\x - 1.4)/0.25)/0.5 + 0.1});
     % sum
-    \draw <6> [fill=white, white, opacity=0.5] (-2.7,0.1) rectangle (3,2.7);
+    \draw <6> [fill=white, white, opacity=0.5] (-2.7,0.05) rectangle (3,2.7);
     \draw <6> [domain=-2.6:2.9, smooth, variable=\x, yellow, very thick]
                 plot ({\x}, {exp(-(\x + 1.1)*(\x + 1.1)/0.25)/0.5 +
                              exp(-\x*\x/0.25)/0.5 +