0                         0
                        -1                         0
                         1                         0
                         0                        -1
                         0                         1
                      -0.5                         0
                       0.5                         0
                        -1                        -1
                         1                        -1
                        -1                         1
                         1                         1
                         0                      -0.5
                         0                       0.5
                     -0.75                         0
                     -0.25                         0
                      0.25                         0
                      0.75                         0
                      -0.5                        -1
                       0.5                        -1
                      -0.5                         1
                       0.5                         1
                        -1                      -0.5
                         1                      -0.5
                        -1                       0.5
                         1                       0.5
                         0                     -0.75
                         0                     -0.25
                         0                      0.25
                         0                      0.75