code: function fixCurves() {
                          if (point[0] == 0) start = point[1];
                          if (point[0] == 1) end = point[1];
                          var points = filter[curves.name];
                          var foundStart = false;
                          var foundEnd = false;
                          for (var i = 0; i < points.length; i++) {
                              var p = points[i];
                              if (p[0] == 0) {
                                  foundStart = true;
                                  if (point[0] == 0 && p != point) points.splice(i--, 1);
                              } else if (p[0] == 1) {
                                  foundEnd = true;
                                  if (point[0] == 1 && p != point) points.splice(i--, 1);
                              }
                          }
                          if (!foundStart) points.push([0, start]);
                          if (!foundEnd) points.push([1, end]);
                      }
docs: Make sure there's always a start and end node