Using variables to show quiz progress

I am building a quiz where the person has to get 8 questions in a row correct. I guess that I will have to use variables to enable the following two functions:

1) With each correct question, a box appears, on top of others, to indicate progress i.e. correct number of answers/number of boxes builds up

2) if there is a wrong answer, the penalty is to lose 2 boxes.

In order to get going on this, I would appreciate any help.

Thanks