This typeface is born out of the idea of extending or rounding out a given outline of a Letter. For example if the letter line segment is straight, then make it semi-circular, and if the letter line segment is already round, then make it angular. This interchangeable rule is at the heart of every letter & number shown. Every letter inline remains the same, it is only the outline and the fill-in that make the letters appear thicker and different.
The difficulty arose in deciding the starting condition of the letter, for example, I could say that the default J has a top serif, or also argue that it doesn't. Also, what constitutes a line segment? For letters like 'B', is it two small 'D's stacked on top of each other, or a single 'I' with a '3'? In each composition, the B would look the same, but the individual components are clearly different. Finally, a related question, was whether a line segment should be made Concave versus Convex.
I would next like to explore the Non-triviality of letters that are transformations of one another, such as 'N' and 'Z', or 'W' and 'M' or lowercase 'p' 'q' 'b'. Consistency and Readability have muddy thresholds.