boundary_types = p,p
boundary_values = 0,7
initial_gradients =      -0.2, -0.3,    0,  0.3,    1,    3,  -20,   -3
reflection_path = (1,2),(2,2),(1,3),(2,3),(1,3),(2,4),(1,3),(1,4),(1,3),(0,4)
grid_size = 5
max_radius = 70%
