well... didn't I give you a link and a hint?
More hint:
to become invisible, you can wrap yourself in the code of conduct which can be viewed by clicking the button on the door leading into the Queen Upper Organisation For Terrorism Eradication (I also mentioned this in the Extension 1 forum).
to reveal the invisible, you can picture them and draw them out from your heart and select what you want from the many pictures which come up.
Oh, last thing: some of the "by inspection" reasons in my solutions are rather inappropriate... basically I was bored and there has been a trend towards using "by inspection" technique in this forum.