Fun interview with Loren Brichter (is anything involving Loren ever not fun?), sharing some of the behind the scenes info on how Letterpress came about and how Loren likes to work:

In the case of Letterpress, we played rough prototypes as I fleshed out the guts. Tweaks and polish happened in parallel as I finished off features; I like jumping back and forth between a few different things to let my subconscious chew on one problem while my conscious works on something else.

Startup Juicer Interviews Loren Brichter