The graduate (g-rated)

Today Dennis' class had a little graduation party. His teacher asked them to raise their hands if they wanted to tell something they had learned this year in Kindergarten.  Dennis raised his hand but kept squirming out of his chair in his eagerness to share.  When he finally remained seated, she called on him and he had forgotten what he so desperately wanted to say. She asked what he'd learned in science, and he said they'd learned all the shapes.  She asked him to name a shape that he'd learned.  I don't know what I was expecting him to say, but it wasn't "rectangular prism", which was his answer.  He received his diploma and celebrated with his friends, and now he has finished his first year of elementary school.  Summer, here we come!