The frame list conversation

@Matt-Esch opened a gist https://gist.github.com/Matt-Esch/7096695844456080693a

sharing concerns about the direction of mercury & modularity

This PR contains the examples in his gist unedited.

I will make a series of atomic commits changing the code to address his concerns and apply the mercury global constraints.

This PR can be used as a back and forth discussion by leaving comments on the individual commits.