Lift

a lift moves between a number of floors.
a lift has a panel of buttons passengers can press to request floors.
people can call the lift from other floors. A call has both a floor and a desired direction.
a lift has doors which may be open or closed.
a lift fulfills a request when it moves to the requested floor and opens the doors.
a lift fulfills a call when it moves to the correct floor, is about to go in the called direction, and opens the doors.
a lift can only move between floors if the doors are closed.

When you have a single lift working, you may want to tackle these further features:

there can be more than one lift.
only one lift needs to respond to each call.
on each floor there is a monitor above each lift door. While the lift is moving it shows which floor it is on.
when the lift stops at a floor to answer a call, the monitor shows which direction it will go in.
when fulfilling a call, the relevant lift makes a ‘DING’ as it opens the doors.

This kata is described on Kata-Log but I have changed it slightly.

Referenced in these Learning Hours: