diff --git a/examples/Wave1D_Sismo_Day4.jl b/examples/Wave1D_Sismo_Day4.jl
index 5a89504..cf60548 100644
--- a/examples/Wave1D_Sismo_Day4.jl
+++ b/examples/Wave1D_Sismo_Day4.jl
@@ -77,7 +77,7 @@ function MainSource()
         @. ε̇.xx = ∂Vx∂x - 1/3*∇V
       
         # Stress update
-        @. τ.xx = f_shear(G,1.0e5,Δt)*Δt*(ε̇.xx) + f_relax(G,1.0e5,Δt)*τ.xx
+        @. τ.xx = f_shear(G)*Δt*(ε̇.xx) + f_relax(G)*τ.xx
 
         # Pressure update 
         @. P    = P - Δt*f_bulk(K)*∇V
@@ -114,4 +114,15 @@ function MainSource()
 
 end
 
+function f_bulk(K) 
+   return K
+end
+
+function f_shear(G)
+    return 2*G
+end
+function f_relax(G)
+    return 1.
+end
+
 MainSource()
\ No newline at end of file