diff --git a/stl_3d.c b/stl_3d.c
index 6dd3e52..0e05cf6 100644
--- a/stl_3d.c
+++ b/stl_3d.c
@@ -111,7 +111,7 @@ stl_angle(
 	v3_t cross = v3_cross(dx21, dx43);
 	float dot = v3_dot(dx31, cross);
 
-	if (debug)
+	//if (debug)
 	fprintf(stderr, "dot %f:\n %f,%f,%f\n %f,%f,%f\n %f,%f,%f\n %f,%f,%f\n",
 		dot,
 		x1.p[0], x1.p[1], x1.p[2],
@@ -120,7 +120,8 @@ stl_angle(
 		x4.p[0], x4.p[1], x4.p[2]
 	);
 	
-	int check = -EPS < dot && dot < +EPS;
+	//int check = -EPS < dot && dot < +EPS;
+	int check = -1 < dot && dot < +1;
 
 	// if the dot product is not close enough to zero, they
 	// are not coplanar.