If you don’t know what I’m talking about it’s this [here](https://community.spotify.com/t5/Subscriptions/QR-Codes-for-tattoo/td-p/4693922) People can draw them on paper and they still work. They seem to work well and are very simplistic. And there are over 50 millions songs on Spotify, and infinite playlists. How does this work?
In: Technology
There are 23 bars, that can have 8 different sizes. The first and last bar are always the smallest size, and the middle bar is always the largest size (this is done for calibration). That leaves 20 ‘information’ bars with 8 possibilities each, which can have 8^20 unique combinations.
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