This is beautiful: Closures; an Italian Sonnet, by Bruce Williams.
What’s a closure, you ask? Here’s Martin Fowler’s description:
Closures have been around for a long time. I ran into them properly for the first time in Smalltalk where they’re called Blocks. Lisp uses them heavily. They’re also present in the Ruby scripting language – and are a major reason why many rubyists like using Ruby for scripting. Essentially a closure is a block of code that can be passed as an argument to a function call.
So there you have it. The beauty of code, expressed in the form of an Italian Sonnet.