How Copyright Works

• You own expression, not idea
  • The particular sequence of words or bytes
  • Some non-literal elements; e.g. settings and specific characters in a story
  • Young students in magical schools are fair game, but don't call your main character Harry Potter
• Copyright duration, DMCA, SBCTEA; don't get me started
  • Limited term, 'eventually' lapses into public domain
  • Term is now absurdly long
• Public domain
  • Anyone can use for anything
  • Literary classics (Shakespeare, etc.)
  • Things explicitly released into public domain
• Patents & Trademarks
  • Patent: you actually own the idea
    • Can license or not at your discretion
    • Expires after a while
  • Trademark: identifying mark in business
    • Doesn't expire
    • But must be defended