I know a halyard from a sheet, thank you. But a better example is that I've run outdoors on a windy day, which virtually every person ever has done at least once. And yet the overwhelming majority never thought to use a spinnaker on a skateboard. All new inventions, every single one, are one or more old inventions composed together. The novelty lies in the composition, not the components.
I share your antipathy toward software patents though. Mathematical theorems aren't patentable, and programs are just gussied up theorems so they shouldn't be either.
I just don't see as patent-worthy the concept of sticking a sail on something to allow the wind to push it. Sails have been around for thousands of years.
It's as lame as adding a wheel to something so it will roll instead of slide. Or putting a sign on something with instructions. Or putting an ON button on a device.
I share your antipathy toward software patents though. Mathematical theorems aren't patentable, and programs are just gussied up theorems so they shouldn't be either.