model Test
  parameter Real k = 1.0;
  input Real u;
  Real x(start = 10.0);
  Real y;
  Real z;
  output Real w;
equation
  when sample(0.0, 0.1) then
    z = pre(x);
  end when;
  w = 2 * z;
  der(x) = k * x + u;
  y = x ^ 2;
end Test;