This is the companion app to my article on concurrency in iOS

Concurrency Explained: Sync vs Async, Serial vs Concurrent

• Clone the repo, open xcworkspace and build locally (requires Xcode 11)
• Or download the public beta directly on your device

The app runs on iOS 13.0+ (it's in SwiftUI). It's optimized for iPhone X screen or larger, so I recommend not picking something smaller than an iPhone X simulator.

It includes a 10-question concurrency quiz. I suggest trying it before and then again after reading the article to see how your score changes

There is also a visual explanation of synchronous and asynchronous execution, as well as serial and concurrent queues.