Big black balls

was a topic of conversation in my class yesterday. Yeah.

We were talking about lines and how solutions are the same thing as points and how there are an infinite number of solutions (points) on any line.  I had a picture of a line up and we were naming points on the line and I was putting a black dot on each point a student named on the line. Suddenly one (very innocent) student understood what I was getting at and raised his hand and said "There are an infinite number of big black balls all over that line!" My class (and I) lost it.  For the rest of the day any time I asked how many solutions a linear equation has I would have a chorus of "infinite big black balls" shouted back at me. I guess at least they'll never forget.