The Limit stamp (lim)

When I was taking a calculus class my junior year here at UNH, my professor (an amazing teacher/tutor) spoke about how much she would love if someone made her a limit stamp. I had forgotten about her plead to the class until I came to her with another prop idea for the 3D printing prop assignment. Without getting my idea fully out in words, she stopped me and said: " Please tell me, you are making my limit stamp". It had been decided: the prop assignment for me would be the limit stamp. What is