Can someone help me with a epitaph?

I know this isn’t the place for this but I need help!! I have to write one for my English class. It has to be a b a b rhythmic scheme. I would like to write one about Macbeth but i need help. The last time I wrote one with that scheme my teacher told me it was wrong. I don’t want someone to do all the work for me, I genuinely need help. And I’d appreciate anything. It has to be 12 lines.