As they say, "pictures are worth a thousand words." The english language is vague and often what you think you're saying is not interpreted the same by the person receiving it. Digital cell phone pictures that you modify with some arrows pointing to the subject area, etc. are cheap.
I know you think you understand what you thought I said but I'm not sure you realize that what you heard is not what I meant.
"I KNOW THAT YOU BELIEVE YOU UNDERSTAND WHAT YOU THINK I SAID, BUT I AM NOT SURE THAT YOU REALIZE THAT WHAT YOU HEARD IS NOT WHAT I MEANT."