The Set
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
A set is an abstract data type representing an unordered collection of unique elements — less functionality than a list, and the reduction buys more efficient representations.
Show
The places someone wants to visit form a set: no order, no duplicates, membership the only question.
Watch for
Losing order is the price of the speed.