Hard Constraints Only, For Now
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
A hard constraint makes a combination flatly legal or illegal; a soft constraint merely prefers some assignments to others — and this unit is hard constraints only.
Show
"The drummer cannot be on two stages at once" is hard; "the headliner would rather play late" is soft.
Watch for
Preference gets its own arithmetic in Unit 7 — a declared scope, not an oversight.