diff --git a/galton.pdf b/galton.pdf
index 21523fc..345ad3d 100644
Binary files a/galton.pdf and b/galton.pdf differ
diff --git a/material/ab1.pdf b/material/ab1.pdf
index 1a96dfe..0fc3139 100644
Binary files a/material/ab1.pdf and b/material/ab1.pdf differ
diff --git a/material/ab1.tex b/material/ab1.tex
index b7e4b0b..4dde3f9 100644
--- a/material/ab1.tex
+++ b/material/ab1.tex
@@ -335,22 +335,22 @@
 					\node at (12.25,14.1875) {$\binom{1}{1}=$};
 					
 					\draw (10.25,13.5) rectangle (13,12.125);
-					\node at (10.875,12.8125) {$\binom{2}{0}=$};
+					\node at (10.875,12.8125) {$\binom{2}{1}=$};
 					
 					\draw (7.5,13.5) rectangle (10.25,12.125);
-					\node at (8.125,12.8125) {$\binom{2}{1}=$};
+					\node at (8.125,12.8125) {$\binom{2}{0}=$};
 					
 					\draw (13,13.5) rectangle (15.75,12.125);
 					\node at (13.625,12.8125) {$\binom{2}{2}=$};
 					
 					\draw (11.625,12.125) rectangle (14.375,10.75);
-					\node at (12.25,11.4375) {$\binom{3}{0}=$};
+					\node at (12.25,11.4375) {$\binom{3}{2}=$};
 					
 					\draw (8.875,12.125) rectangle (11.625,10.75);
 					\node at (9.5,11.4375) {$\binom{3}{1}=$};
 					
 					\draw (6.125,12.125) rectangle (8.875,10.75);
-					\node at (6.75,11.4375) {$\binom{3}{2}=$};
+					\node at (6.75,11.4375) {$\binom{3}{0}=$};
 					
 					\draw (14.375,12.125) rectangle (17.125,10.75);
 					\node at (15,11.4375) {$\binom{3}{3}=$};