Flatmates Dave and Tony had a simple agreement. Each Saturday Tony would buy a five pack of doughnuts on the way back from his run and put them in the kitchen. Dave was welcome to share them, with the only stipulation being that he leave the last one for Tony. This arrangement worked well enough for about a month. Then, one morning after earlier having two each, Tony went to make a cup of coffee and to have the last doughnut.
“Dave, did you eat the last doughnut?” he shouted irritably.
“No,” his roommate replied.
“Then where did it go?”
“You ate it,” Dave responded.
“This morning at breakfast,” Dave said.
“I never did!”
“Yes, you did. You see, when you brought them in and then went for your shower, I opened the box and reversed the order of the doughnuts. So, you ate the last one at breakfast, and I helped myself to the first one a little while ago. It’s all a matter of perspective.”