#include <memory>
    #include <list>

    struct Grass {
        struct {
            int x, y;
        } position;
    };

    int main() {
        std::list<std::unique_ptr<Grass>> grassList;
        for(int i=0;i<50;i++){
            for(int j=0;j<50;j++){
                auto g1 = std::make_unique<Grass>();
                g1->position.x = i;
                g1->position.y = j;
                grassList.push_back(std::move(g1));
            }
        }   
    }