What is happening right now?

spawning = adding an object to the world You have to replace line 1 of your last shown code with the line given.

Yes. You will find the answers there. It is the part labelled: <Code Omitted>in the moveVertically method.

You have a grave misunderstanding about extending classes. An extension to a class, in design, is to modify or sub-classify a type of object. For example, if you had an Insect class, its extensions could feasibly be Fly, Bee, Moth, Locust, JuneBug, etc. All objects created from these extensions are still Insect objects. A Counter object is clearly not a MiddleInvisible object. There are multiple previous discussions dealing with keeping a current score when changing worlds. Do a search and check some out.