What’s the simplest thing that can possibly work and still be called Scrum?

What Scrum “says” you have to do comes up plenty with teams I work with. Many have a difficult time remembering all the rules and get hung up in what they are. Or people blame Scrum for various reasons, like it insists on all these meetings or doesn’t allow for any up-front nor long-term thinking. That self-organization means hands-off.

What are the rules, or the constraints of Scrum for teams to evaluate themselves against? What can people remember easily? It’s something I tried to discuss a bit in this message. Don’t do stupid crap was my favorite response. I have decided to add these “rules” as the bonus set* when introducing the Scrum Framework:

3 Sets of 3
3 Roles
Scrum Master, Product Owner and (Delivery) Team

3 Artifacts
Product Backlog, Sprint Backlog and Burndown Chart

3 (now 4) Ceremonies
Planning (daily and Sprint), Review and Retrospective

*Bonus Set
3 “Rules”
Do Something, Self-Organize, Inspect & Adapt

As I was writing this I see that Ron Jeffries thinks that “Scrum is OK …”. What do you think? Is this too simple? Not simple enough? Is it barely sufficient to be called Scrum?