diff --git a/mat3/mat3.go b/mat3/mat3.go
index 078a109..675ebff 100644
--- a/mat3/mat3.go
+++ b/mat3/mat3.go
@@ -178,8 +178,8 @@ func (mat *T) AssignMat2x2(m *mat2.T) *T {
 func (mat *T) MulVec3(v *vec3.T) vec3.T {
 	return vec3.T{
 		mat[0][0]*v[0] + mat[1][0]*v[1] + mat[2][0]*v[2],
-		mat[0][1]*v[1] + mat[1][1]*v[1] + mat[2][1]*v[2],
-		mat[0][2]*v[2] + mat[1][2]*v[1] + mat[2][2]*v[2],
+		mat[0][1]*v[0] + mat[1][1]*v[1] + mat[2][1]*v[2],
+		mat[0][2]*v[0] + mat[1][2]*v[1] + mat[2][2]*v[2],
 	}
 }
 
diff --git a/vec3/vec3.go b/vec3/vec3.go
index 23f6e27..3ee8b60 100644
--- a/vec3/vec3.go
+++ b/vec3/vec3.go
@@ -107,10 +107,12 @@ func (vec *T) LengthSqr() float32 {
 }
 
 // Scale multiplies all element of the vector by f and returns vec.
-func (vec *T) Scale(f float32) {
+func (vec *T) Scale(f float32) *T {
 	vec[0] *= f
 	vec[1] *= f
 	vec[2] *= f
+	
+	return vec
 }
 
 // Scaled returns a copy of vec with all elements multiplies by f.