Border Control

You run the Schengen entry desk.

Ten travellers, ten document sets: a passport, perhaps a visa, a ticket out and a history of stamps. Check the visa, the passport dates, the 90/180-day rule and the onward ticket, then admit or refuse. If you refuse, name the rule they broke.

The travellers and documents are fictional and the rules are simplified. About 5 minutes. Free, no account, nothing to install.