Key points are not available for this paper at this time.
Any stimulus to a system such as described in this paper can be coded into a binary representation. A character on a piece of paper can be represented in binary form by dividing the paper into many small squares and assigning a 1 to a square if the character covers that square, and a 0 to the square if the character does not cover it.
R. L. Mattson (Thu,) studied this question.