Some people punctuate their sentences if they have to.
There is an answer and this will make sense. Try this: "That that is, is. That that is not, is not. Is that it? It is!" --- There is no way the sentence can be punctuated because it doesn't make...
Always with a comma
There should be a period after it: etc.
The only way to end a sentence with parenthesis is to put the entire sentence in parenthesis. (Though that isn't very common.)