Figure 7 shows the data flow in REC/F, which is not very extensive. There is essentially one array, of ample dimension, which will hold the coordinates of any polygon which is likely to be used. The coordinates are stored in projective form, because that is also the way that the coefficients of lines will be stored and maintains duality. This array acts as an accumulator, which can be modified, to and from which data can be transported, and which is the reference for figure drawing.
There is also a pushdown list, not much used by REC/F, in which data can be stored or read, and eventually removed as it is recovered. Finally, there is a graphing area, in which the polygons are drawn, one by one. The auxiliary area copies the first, but changing the position of its image reflects back in the small view because there is an additional coordinate adjustment. This latter will probably get replaced by a full projective transformation of the plane, being the most convenient place to overcome the limitations on reflecting and rotating inherent in Draw and other programs.
There are some operators which generate polygons, the most important of which is Xn for generating a regular n-gon with a vertical rightmost edge. It is the only one formally listed in the rectbl header, but as time goes on and interest centers on particular irregular polygons, more will undoubtedly be added.
