settings = {"velocity_min": 1,
            "velocity_max": 3,
            "x_boundary": 800,
            "y_boundary": 800,
            "small_particle_radius": 5,
            "big_particle_radius": 10,
            "number_of_particles": 500,
            "density_min": 2,
            "density_max": 20
           }
settings = {"velocity_min": 1,
            "velocity_max": 3,
            "x_boundary": 800,
            "y_boundary": 800,
            "small_particle_radius": 5,
            "big_particle_radius": 10,
            "number_of_particles": 500,
            "density_min": 2,
            "density_max": 20
           }