┌─────────────── ⇦ ───────────────┐
    │             ┌ ⇦ ┐ ┌─── → ─── Monitor
┌ object ── → ── shareable 
└ ⇦ ┘               │   └── → ── transactable
                    └─────── ⇦ ───────┘

I've got → representing is-a relationships and ⇨ representing can-contain relationships.