diff --git a/examples/FTCS_2D_proto_example.cpp b/examples/FTCS_2D_proto_example.cpp
index 5f159bb..27dd892 100644
--- a/examples/FTCS_2D_proto_example.cpp
+++ b/examples/FTCS_2D_proto_example.cpp
@@ -29,7 +29,7 @@ int main(int argc, char *argv[]) {
     // (optional) set the concentrations, e.g.:
     // MatrixXd concentrations = MatrixXd::Constant(20,20,1000); // #row,#col,value
     // grid.setConcentrations(concentrations);
-    MatrixXd concentrations = MatrixXd::Constant(row, col,1);
+    MatrixXd concentrations = MatrixXd::Constant(row,col,0);
     concentrations(0,0) = 2000;
     grid.setConcentrations(concentrations);