Teaching the AS/400 to Play Cards, Part 2

At the time, company rules allowed leave in half-day units. That small detail made a single running balance less intuitive than it first appeared.

I imagined giving each employee one card for each day of entitlement. The suit would show the kind of leave: spades for special leave, hearts for annual paid leave, diamonds for substitute leave, and clubs for other leave.

During the monthly check, someone who had taken one special-leave day would return one spade. Someone who had taken two paid-leave days would return two hearts.

This made both the type and remaining quantity easy to understand. It translated an abstract policy into objects people already knew how to count.

But it also concealed a serious trap. A card had more than a type and a quantity; it had a life cycle.