* A new instance of GR::Plot is created each time. Previous settings are not obtained. You have to manage it yourself. * A new instance of GR::Plot is created each time. It refers to the previous settings. * A new instance of GR::Plot is created. One instance is used repeatedly. Multiple instances may exist at the same time. * A new instance of GR::Plot is created. One instance is used repeatedly. It is desirable to have only one instance. * There is an instance that holds the settings out of the Plot instance itself. * Stop adding class methods to the GR module and make Plot more object-oriented. * Choose the wrong way to maintain state in the module for some benefit * None of the above