Update: We mistakenly noted in an earlier version that Chaudhri had been a part of Microsoft’s Hololens team. The story has been updated to remove the reference.

In his two decades at Apple, Imran Chaudhri worked on many of the company’s most iconic product lines, including the iPhone, iPad and Mac. The designer left the company in 2017 , but today he’s offering up some fun insight into Apple Watch’s beginnings on the wearable’s fifth birthday.

The thread is a treasure trove of fun facts about the device’s early days. One interesting tidbit that might not be a huge surprise to those following Apple at the time is that an early prototype of the Watch consisted of an iPod nano strapped to a watch band.

my first prototype was built on a 6th gen nano strapped to this band. i had just wrapped up ios5 and took it down to show the ID team what notification centre and siri was – and what it could be in the future. i never got to share it with steve. we lost him right after ios5. pic.twitter.com/j4JJYNIgIu — Imran Chaudhri (@imranchaudhri) April 24, 2020

Five years before it finally entered the smartwatch market in earnest, Apple introduced a square touchscreen nano. Three years before the arrival of the first Pebble, people were already considering the smartwatch possibilities. Accessory makers quickly took advantage, introducing wrist bands that would let it function as a touchscreen music watch. That sixth-gen product ultimately served as a foundation for the popular device to come.

Per Chaudhri:

i had just wrapped up ios5 and took it down to show the ID team what notification centre and siri was – and what it could be in the future. i never got to share it with steve. we lost him right after ios5.

Other interesting bits here include: