Function burning_ship

Main.cpp:68–73

  y = ny;
}
void burning_ship(double& x, double& y, double cx, double cy) {
  double nx = x*x - y*y + cx;
  double ny = 2.0*std::abs(x*y) + cy;
  x = nx;
  y = ny;
}
void feather(double& x, double& y, double cx, double cy) {
  std::complex<double> z(x, y);
  std::complex<double> z2(x*x, y*y);