struct machine {
  depth at;
  int x, y;

  machine(grid const& bit, int xyspeed, int zspeed, int maxspeed);
  void move(int x, int y, depth at);
  void cut(int x, int y, depth at);
  void stop();

 private:
  depth mat;
  int mx, my, mspeed;
  const int bitx, bity;
  const int xyspeed, zspeed, maxspeed;
  const int res_per_meter;
  void go(int x, int y, depth at, int speed);
  void finish();
};