There's a blog post going around that tries to reconstruct a J Dilla beat from its source. (Spoiler: it's very hard.) The creation of hip-hop beats is pretty misunderstood, as a lot of fans hear a sample and assume that you just lay a heavier beat over it and you're done. And some of the laziest sampling over the past 20 years hasn't really helped that -- there's a wide spectrum of quality and craftsmanship with any group of music makers. But J Dilla is one of the most amazing craftsmen ever in hip-hop. Look this up on WhoSampled -- you'll be amazed.