Thanks for sharing. Complex examples like these are great to highlight syntax which simpler examples never mention. For example (heart rate sensor excerpt):

    remembered_ = List width/2: initial_value
    half_height := height / 2
    ...
    min_value := remembered_.reduce: | a b | min a b

These lines (with seemingly context-sensitive meanings for the / and : characters) feel less obvious to me than the examples on the home page.