An example of learning without boundaries:
One day, I decide I want to play the guitar. I get my hands on one and fiddle around. Perhaps a brief history on the instrument will give me some better context as to why the instrument is shaped as it is, and what all the features are. An exposure to famous guitarists and their music improves my appreciation of music and gives me context to work with. As I continue to struggle with notes and basic music theory, it may be a good time to take a brief detour into the realm of physics - a lesson in simple harmonics. If interested, I can dive further into the required algebra relevant to harmonic equations. Hmm... maybe learning to use a computer program can help me figure out how messing with these waves changes the sound...
And so it goes. A familiar story to most hackers, but sadly an approach that most educational systems do not encourage.
Is this exploratory form of learning superior? My theory is that the associations formed between nodes of knowledge are necessary for any sort of actual deep learning to occur. By sandboxing subjects, the standard school curriculum limits the possible associations that students think are allowed, thus limiting the probability of successful links between nodes. Even an above average student can graduate from college, and be left with nothing but a bunch of barely reachable random islands of knowledge, floating further out to sea every day.
In other words: school sucks, learning rules.