Hehe, this reminds me of the "impossible chat room" I did several years ago.

An online game I was working on wanted to have a chat room, so I wrote up a little java applet that sent some simple messages back and forth (I think it was also designed to send some control signals as well as textual messages)

My boss (who we called the Crazy Old Man) was adament that we needed a Refresh button.
I told him it would be fine, we could just populate the display with messages as they came in.
Nope, impossible.
Couldn't do it.

So I did it.
I actually added a Refresh button, as well.
When you clicked it, it wrote "Crazy" to the chat log.