> Principles of UI, A Thread:
> 1. natural mapping
> 2. visibility of system state
> 3. discoverability
> 4. constraints and affordances
> 5. habits and spatial memory
> 6. locus of attention
> 7. no modes
> 8. fast feedback
> 9. do not cause harm to a user's data or through inaction allow user data to come to harm
> 10. prefer undo to confirmation boxes. For actions that can't be undone, force a "cooling off" period of at least 30 seconds.
> 11. measure using Fitt's, Hick's, GOMS, etc. but always test with real users.