text: #include <matplot/matplot.h>
  
  int main() {
      using namespace matplot;
      std::tuple<vector_2d, vector_2d, vector_2d> C;
      auto &[r, g, b] = C;
      r = transform(vector_2d{{.1, .2, .3}, {.4, .5, .6}, {.7, .8, .9}},
                    [](double x) { return x * 255; });
      g = zeros(3, 3);
      b = zeros(3, 3);
  
      image(C);
  
      wait();
      return 0;
  }