Ask HN: What kind of whiteboard does not use dry erase markers?

A long time ago, a colleague and I visited a supplier in another state. While we were waiting alone in a conference room, we noticed an unusual looking note taking device at the front of the room. It was a very large easel that looked like a white board, with a tray of markers and an eraser. But it was clearly electronic because it had stuff attached to the top and bottom, some buttons, and was plugged in. We walked up to the easel, drew a large circle on it, and pressed what looked like a COPY button, curious how it was going to perform that task.

The machine whirred into action, scrolling the white board material (which turned out to be a flexible plastic-like film) over the top of the easel, and paying out fresh whiteboard up from the bottom. A perfect duplicate of our circle on paper spat out of a slot in the machine, akin to a FAX machine. As the scrolling came to a stop, it revealed a previously hidden drawing -- someone had drawn a large "X" in the middle of the page. I guess we weren't the only ones who were curious how the machine worked.

In the 1990s, I went to a lab in Tokyo for a presentation, and they had me using a freestanding whiteboard. When the board got full, I grabbed the eraser but a few in the audience started going "wait! wait". I thought they needed more time to copy the writing, but then a guy came up from the audience and pressed a button at the side of the board. The writing surface scrolled off to the side and a printout emerged from a machine in the corner.