The students all nodded in agreement: Teacher Mary was a force to be reckoned with.

"I had her for algebra," said Sarah, a junior. "I thought I was doing great, but then she gave me a C-minus on a test. I asked her to explain, and she just smiled and said, 'You didn't think outside the box, dear.'"

Years later, when Oakdale High School celebrated its 50th anniversary, the alumni association invited Mary to receive a special award for her dedication to teaching. As she stepped up to the microphone, a sea of familiar faces gazed back at her, some with nostalgia, others with a hint of fear.

"I had her for geometry," chimed in Alex, a senior. "She made us build a scale model of the school using only a ruler and a compass. It took me hours, but when I presented it, she told me I'd gotten the scale wrong... by a factor of ten!"