diff --git a/docs/lib3x-nz_perlin1.md b/docs/lib3x-nz_perlin1.md
index 716a7907..9877f5ec 100644
--- a/docs/lib3x-nz_perlin1.md
+++ b/docs/lib3x-nz_perlin1.md
@@ -15,7 +15,7 @@ Returns the 1D [Perlin noise](https://en.wikipedia.org/wiki/Perlin_noise) value
     use <util/rand.scad>;
     use <noise/nz_perlin1.scad>;
 
-    seed = rand();
+    seed = rand(0, 255);
     polyline_join([for(x = [0:.1:10]) [x, nz_perlin1(x, seed)]])
 	    circle(.05);