diff --git a/src/sand-wedge-data/twopiece.hh b/src/sand-wedge-data/twopiece.hh
index 02872d666f95fb3a595674702c1b7bb85f033e7e..0454d6fc42f46a1d875ea643cc3e7faf3ed41bcf 100644
--- a/src/sand-wedge-data/twopiece.hh
+++ b/src/sand-wedge-data/twopiece.hh
@@ -14,21 +14,17 @@ class TwoPieceFunction
   bool liesBelow(Dune::FieldVector<double, MY_DIM> const &x,
                  Dune::FieldVector<double, MY_DIM> const &y,
                  Dune::FieldVector<double, MY_DIM> const &z) const {
-    return (z[0] - x[0]) * (y[1] - x[1]) / (y[0] - x[0]) >= z[1] - x[1];
+    return x[1] + (z[0] - x[0]) * (y[1] - x[1]) / (y[0] - x[0]) >= z[1];
   };
   bool insideRegion2(Dune::FieldVector<double, MY_DIM> const &z) const {
-    return liesBelow(_K, _M, z);
+    return liesBelow(MyGeometry::K, MyGeometry::M, z);
   };
 
-  Dune::FieldVector<double, MY_DIM> const &_K;
-  Dune::FieldVector<double, MY_DIM> const &_M;
-
   double const _v1;
   double const _v2;
 
 public:
-  TwoPieceFunction(double v1, double v2)
-      : _K(MyGeometry::K), _M(MyGeometry::M), _v1(v1), _v2(v2) {}
+  TwoPieceFunction(double v1, double v2) : _v1(v1), _v2(v2) {}
 
   void evaluate(Dune::FieldVector<double, MY_DIM> const &x,
                 Dune::FieldVector<double, 1> &y) const {