20 20
xxxxxxxxxxxxxxxxxxxx
x                  x
x x  GGGGGG      x x
x   xxxxx  xxxxx   x
x                  x
x x      xx      x x
x x x x  xx  x x x x
x x      xx      x x
x x x x  xx  x x x x
x x            G x x
x x     o      G x x
x x xxx      x G x x
x x  ux      x G x x
x x xxx      x G x x
x     o    O     x x
xx                xx
    xxxxx  xxxxx    
xxx              xxx
x    GGGGGGG       x
xxxxxxxxxxxxxxxxxxxx