It’s a random selection of three Apple Watch straps, officially from Apple, that you’ve added to your collection.
The app can choose either the same or different straps, and it refreshes every day.
I came across this concept while working on a computer science homework assignment. I learnt about subsets and unions when I saw it categorised bands by generation, color, or collection. Combinatorics, isn’t it? The Bandbreite app provided a great example of how permutations and randomised algorithms work together.
I’ve reached out to the developer, @choreographics , to learn more about how his development team curated the band collections and made them synonymous with Apple’s design.
If it picks the same straps I wore earlier in the week I would ask Siri to pick a random colour. I ask Siri again if she picked the colour that is the same on bandbreite.