diff --git a/apps/tutorials/pe/01_ConfinedGas.cpp b/apps/tutorials/pe/01_ConfinedGas.cpp
index 137194ce636f56f9590ae476d9415b7b9849c0c8..c3b4a3af84cb22f18b76d9c99a47942c7476fbb4 100644
--- a/apps/tutorials/pe/01_ConfinedGas.cpp
+++ b/apps/tutorials/pe/01_ConfinedGas.cpp
@@ -166,14 +166,13 @@ int main( int argc, char ** argv )
    auto generationDomain = simulationDomain; // simulationDomain.getExtended(-real_c(0.5) * spacing);
    //! [Planes]
    PlaneID xPosPlane = createPlane(*globalBodyStorage, 0, Vec3(1,0,0), simulationDomain.minCorner(), material );
-   PlaneID xNegPlane = createPlane(*globalBodyStorage, 0, Vec3(-1,0,0), simulationDomain.maxCorner(), material );
+   createPlane(*globalBodyStorage, 0, Vec3(-1,0,0), simulationDomain.maxCorner(), material );
    createPlane(*globalBodyStorage, 0, Vec3(0,1,0), simulationDomain.minCorner(), material );
    createPlane(*globalBodyStorage, 0, Vec3(0,-1,0), simulationDomain.maxCorner(), material );
    createPlane(*globalBodyStorage, 0, Vec3(0,0,1), simulationDomain.minCorner(), material );
    createPlane(*globalBodyStorage, 0, Vec3(0,0,-1), simulationDomain.maxCorner(), material );
    //! [Planes]
    
-   raytracer.setBodyInvisible(xNegPlane);
    raytracer.setBodyInvisible(xPosPlane);
 
    //! [Gas]
diff --git a/src/pe/raytracing/Intersects.h b/src/pe/raytracing/Intersects.h
index ec5f1267a6a09f40da610eb55e8b4ab3aa518dfd..3b274630ea4d8fc63bbcba64f23d675a9569897a 100644
--- a/src/pe/raytracing/Intersects.h
+++ b/src/pe/raytracing/Intersects.h
@@ -1,3 +1,23 @@
+//======================================================================================================================
+//
+//  This file is part of waLBerla. waLBerla is free software: you can
+//  redistribute it and/or modify it under the terms of the GNU General Public
+//  License as published by the Free Software Foundation, either version 3 of
+//  the License, or (at your option) any later version.
+//
+//  waLBerla is distributed in the hope that it will be useful, but WITHOUT
+//  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+//  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+//  for more details.
+//
+//  You should have received a copy of the GNU General Public License along
+//  with waLBerla (see COPYING.txt). If not, see <http://www.gnu.org/licenses/>.
+//
+//! \file Intersects.h
+//! \author Lukas Werner
+//
+//======================================================================================================================
+
 #pragma once
 
 #include <pe/Types.h>