diff --git a/source/exercises100.ktx b/source/exercises100.ktx
index 837d273..0adcf6a 100644
--- a/source/exercises100.ktx
+++ b/source/exercises100.ktx
@@ -201,9 +201,7 @@ Create a 8x8 matrix and fill it with a checkerboard pattern (★☆☆)
 hint: array[::2]
 
 < a19
-Z = np.zeros((8,8),dtype=int)
-Z[1::2,::2] = 1
-Z[::2,1::2] = 1
+Z = np.array([[(i + j) % 2 for j in range(8)] for i in range(8)])
 print(Z)
 
 < q20