Professor McKinnon teaches me ring theory this term. He finished his undergraduate degree in Harvard, and then got his PhD in UC Berkeley. He is definitely one of my favourite professor. Here comes some interesting stories he told in class.

One day he was erasing the board and suddenly thought of something. He started the story.

"There was a professor who gave really good lecture.  He came to the classroom exactly on time whenever he had a lecture, but he then spent 10 minutes erasing the blackboard and then gave 40 minutes of exciting lecture. The students felt that their time was wasted so one day, two students decided to do the prof a favour. The arrived at the classroom 10 minutes earlier, and erased the board until it was as clean as a new one. The prof arrived at the classroom, again, on time. He walked to the blackboard and he stopped in front of it. The students were eagerly waiting for him to start the lecture. After seconds of anxious silence, the prof walked towards the eraser, picked it up, and started to erase the board. It again took him 10 minutes to erase the board! When asked by students why he wanted to clean the board which was already cleaned, the prof answered, 'I need this 10 minutes to prepare for lecture!'"

I am tired today. So just one story. I will put more on tomorrow.