Yes, the functional programming way of deferring callbacks to other callbacks. I like it :)
It's really amazing sometimes how powerful divide-and-conquer logic can be. I like it how top-down thinking allows "start with a program definition, break it up, break those problems up, and keep coding until all your functions are implemented".
If you control what you name your functions and your modules as you go, it can be really beautiful. I have a application-specific SOAP module I wrote, the code is elegant as heck, but I read it and wonder "It's a miracle this thing works as simple as the methods and API are...". Thinks just happen. And they just work. Because you told them to. Neat.