错误：无法找到符号，对象已声明，但无法查看公共变量

Im getting the

我得到了

systemB\Plumber.java:44: error: cannot find symbol
            FilterOut.Connect(FilterWildPoints.pipe1);
                                              ^
symbol:   variable pipe1
location: variable FilterWildPoints of type MiddleFilter
systemB\Plumber.java:56: error: cannot find symbol
            FilterWildPoints.pipe1.start();
                            ^
symbol:   variable pipe1
location: variable FilterWildPoints of type MiddleFilter
2 errors
systemB\Plumber.java:4