On the many styles for \mathbb

[topological-modular-forms]

Problem. There are a few distinct approaches to designing \mathbb, and some people prefer certain styles over others. Namely, there is:

1. amsbb, the classic one:

2. txof, the empty-filled one:

3. mathpi, the one where the double strokes are non-curved (such as in e.g. the C):

4. mathpazo and similar styles, the ones that mix bold strokes with double ones:

Design Plan. I plan to:

1. Make an extensive search of the many possible styles for \mathbb.
2. Query the community about the most popular ones.
3. Design versions of \mathbb following the preferred styles in order of preference, with multiple styles being designed as time allows.