I would say what I learned most from the project is that you need to have a well iterated and thought-through design of your product before you start to implement it. Constantly changing the design while you have implemented some of them is time-consuming and contrary to what we hope to achieve, i.e. "rapid" prototyping.
Another point is that API is really powerful. I can imagine how wielding the power could scaffold the implementation of products and the possibilities it creates. I'll keep an eye on it when making other products later and I'm sure I can find some surprises.
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