diff --git a/exercise5/handout_openmp/wave_2d_workshare.c b/exercise5/handout_openmp/wave_2d_workshare.c
index 2c726fd..f131381 100644
--- a/exercise5/handout_openmp/wave_2d_workshare.c
+++ b/exercise5/handout_openmp/wave_2d_workshare.c
@@ -8,7 +8,7 @@
 // TASK: T6
 // Include the OpenMP library
 // BEGIN: T6
-;
+#include <omp.h>
 // END: T6
 
 // Option to change numerical precision
@@ -71,7 +71,8 @@ void domain_finalize(void) {
 // TASK: T7
 // Integration formula
 void time_step(void) {
-  // BEGIN: T7
+// BEGIN: T7
+#pragma omp parallel for
   for (int_t i = 0; i < N; i++)
     for (int_t j = 0; j < N; j++)
       U_nxt(i, j) = -U_prv(i, j) + 2.0 * U(i, j) + (dt * dt * c * c) / (h * h) * (U(i - 1, j) + U(i + 1, j) + U(i, j - 1) + U(i, j + 1) - 4.0 * U(i, j));
diff --git a/flake.nix b/flake.nix
index c1986a7..c09dbd6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -29,6 +29,7 @@
           python3
           pandoc
           bc
+          llvmPackages.openmp
         ];
         shellHook = ''
           echo welcome!