from 2 days ago:
   I ended up looking a little into the brownian distribution. It's an
   equation with a value called D inside a square root and an exponent
   this morning:
   i'm looking into implementing the simple uniform distribution tracing
   idea.
   i'd like to do it with some generality, but working with my short term
   memory issues, it's very hard to discern how much generality doesn't
   expand the problem space too much.
   right now i'm stashing some tiny work with a class called
   UniformDistributionSum to instead use a class called maybe Expr.
   the reason for a more general class is partly to relate with
   introduction of untracked values like ints or ndarrays. Base classes
   that can be shared across parts help make code workable.
   I don't actually have the topical working memory at the moment to make
   something that functions at all, so it's an exploration.