message: Changed wording in 27pt stencil
diff: @@ -7,8 +7,8 @@ $
  \Omega_b = [0,1]^3 (with boundary) \\
  \partial\Omega = \Omega_b \backslash \Omega \\
  u : \Omega \rightarrow R \\
  - u'' = f in \Omega \\
  - u = u_D on \partial\Omega \\
  + u'' = f \in \Omega \\
  + u = u_D \in \partial\Omega \\
  $
  using a finite difference method on an equidistant grid with `K` discretization
  