The copy clerks
You pay your tab at stall A and walk to stall B. What do they say you owe?
One register keeps the master book and three clerks keep copies. The evening plays out in fourteen moments of tabs and prices. The panels show the evening's script, what each book currently says, and a running count of answers that were true a moment ago. Drag the clerks further behind and more of those answers go stale.
Board: The Copy Clerks →Fourteen fixed moments, one master book and three copies. Step through them one at a time.
try this Stay on Copy later, press Play next moment fourteen times, then raise Moments the clerks run behind and watch the stale answers count.
Included with a plan
This lab is included with a plan. The first three lessons of every track are free, with their boards and videos. A plan unlocks every lesson, board, video, lab and paper for one price.
see also Dynamo: Amazon's Highly Available Key-value Store, Time, Clocks, and the Ordering of Events in a Distributed System, Brewer's Conjecture and the Feasibility of Consistent, Available, Partition-Tolerant Web Services, Scaling Memcache at Facebook and Conflict-free Replicated Data Types in Papers.