diff --git a/PerlinNoise.cpp b/PerlinNoise.cpp
index 059d86d..c71bb2e 100644
--- a/PerlinNoise.cpp
+++ b/PerlinNoise.cpp
@@ -44,7 +44,7 @@ PerlinNoise::PerlinNoise(unsigned int seed) : ImplicitSurface(Point(0,0,0)) {
 }
 
 double PerlinNoise::operator() (double x, double y, double z) const {
-    return z - fBm(x, 0, y, 2, 0.3, 2.0);
+    return (y - fBm(x, 0, z, 2, 0.3, 2.0));
 }
 
 double PerlinNoise::noise(double _x, double _y, double _z) const {