Further advances in two-dimensional input-output by typewriter terminals

The purpose of this paper is to describe some new applications in the realm of two-dimensional input-output by typewriter terminal. These applications are extensions of the software and hardware system techniques covered in the references 1--4, 11--21. The principal elements of this approach consist of a versatile programming language and a reverse-indexing typewriter equipped with a special character set. This set permits not only normal alphanumerics but also the construction of arbitrarily-sized symbols by the use of a few interlocking primitive strokes. The reverse-indexing and indexing, together with spacing and backspacing, allow full two-dimensional keyboard control of the typed document. Typing errors are corrected by moving to the desired point and overtyping, or by pressing an "erase" button.