Also, I saw a demo of a similar technology in the 1990s at Sussex University, in which a projector was used to create an interactive table where one could write

Also, I saw a demo of a similar technology in the 1990s at Sussex University, in which a projector was used to create an interactive table where one could write calculations with a pen and the results would appear projected (the numbers having been recognized) and sketches could be augmented with shape-recognition