@Override
  public void step(TestbedSettings settings) {
    super.step(settings);

    addTextLine("Keys: (d) dynamic, (s) static, (k) kinematic");
    // Drive the kinematic body.
    if (m_platform.getType() == BodyType.KINEMATIC) {
      Vec2 p = m_platform.getTransform().p;
      Vec2 v = m_platform.getLinearVelocity();

      if ((p.x < -10.0f && v.x < 0.0f) || (p.x > 10.0f && v.x > 0.0f)) {
        v.x = -v.x;
        m_platform.setLinearVelocity(v);
      }
    }
  }