pull off a senior prank without getting caught

About a week before graduation, myself and 3 buddies bricked up the principals door at night (one of us “found” the office key). We even had a brass name plack engraved with his name on it glued to the center brick. At graduation ceramony, we confessed to our crime. He was a good sport about it, and thanked us for the bricks which he used in a home patio. 3 years ago