The blackboard, and chalk, is probably lost in memory lane and many of the young generation have not seen it or at least not used it. Now the whiteboard with its felt pens is occupying classroom and meeting rooms. In some cases (rich areas) we have seen electronic whiteboards being used. These latter are nice, they can record what you are writing on it, can connect to the internet for sharing your drawings and more but are still quite expensive.
Now University of Tokyo researchers, taking inspiration from e-ink (the screen of your Kindle), have developed a Magneticboard that has several of the advantages of an electronic board but is cheaper.
The idea is to create a screen with two transparent plastic foils embedding tiny beads half white and half black. The black half contains magnetic particles that can be flipped by a magnet or an electromagnetic field (as it is the case with eInk).
The screen can be used as an eInk screen to display text and images but one can also interact with it using a magnetic stylus. Moving the tip of the stylus on its surface flips the beads bringing their black part to the surface. By applying an electromagnetic field one can erase the screen. No power is needed, as in the case of eInk, to keep information displayed.