The single most impressive thing during this project was the sheer integration between the EBTH team and ours. We worked so closely together with their designer, their iOS developer and their product owner. We traveled to Ohio, they traveled here, we shared a daily standup meeting, and we chatted in Slack constantly.
We trained their developer on our toolset. We even pulled the EBTH team into our retrospectives every two weeks, so we could transparently talk through how things were working. That fusion let us work as one team: We were able to rapidly make good decisions because all the stakeholders were working together. We went from idea to the app store with that speed in a few short months.