What are boids? according to wikipedia:
That’s enough to give us an idea, but why would you need Boids? basically it all comes down to the difficulty of animating flocks. A brute force approach is to animate each member individually, a process that is both tedious and time consuming. However instead of animating each member, we can set up a few rules and let them animate themselves.
When I first came across of Boids, I thought it was going to be a complex system of interactions and complicated geometric calculations. This is not true. Boids are in fact simple to understand and easy to implement.
Using Swift and SceneKit I was able to implement a simple Boids simulation
You can see the repo here Swift-Boids