The code here follows the official "Arduino Projects Book".
A soft copy (arduino_projects_book.pdf) is provided here.
The book is part of a larger starter kit that includes accompanying hardware: https://store.arduino.cc/usa/arduino-starter-kit

The code was written with VSCode with the Arduino extension.
The .vscode folder has not been checked in, which contains configs for the Arduino extension such as: board, port, library locations, etc. The folder can be created by doing an "initialize" via the extension.
Further reading on the extension can be found: https://marketplace.visualstudio.com/items?itemName=vsciot-vscode.vscode-arduino

There is nothing special about the code found in this repository as it should be one to one with the code provided in the book/pdf. The final circuits (actual pictures) are provided alongside the code. All 15 projects have been completed.