boundary_types    = p,p
boundary_values   = 0,4
initial_gradients =           -1,   1.1,   -1,   1.5,   10,  -0.4,   1.1,   -1,    1,    10,   -1,  1.1,    -1,   0.4,   10,  -0.4,   1.1,   -1,    1,    10,   -1,  1.1,    -1,   0.4,   10,  -0.4,   1.1,   -1,    1,    10,   -1,  1.1,    -1,   0.4,   10,  -0.4,   1.1,   -1,    1,    10,   -1,  1.1,    -1,   0.5
reflection_path   = (0,-1),(1,-1),(1,0),(0,0),(0,-1),(1,0),(2,-1),(1,-1),(1,0),(2,0),(2,-1),(2,0),(3,0),(3,-1),(2,-1),(3,0),(4,-1),(3,-1),(3,0),(4,0),(4,-1),(4,0),(5,0),(5,-1),(4,-1),(5,0),(6,-1),(5,-1),(5,0),(6,0),(6,-1),(6,0),(7,0),(7,-1),(6,-1),(7,0),(8,-1),(7,-1),(7,0),(8,0),(8,-1),(8,0),(9,0),(9,-1),(8,-1),(9,0)
grid_size         = 10
max_radius        = 90%