Big groups, and building a rotation

A sixty-strong school arriving in four groups of fifteen, each rotating through four activities, is the booking a campsite finds hardest. On the booking, Split into groups lets you name the parts and give each its own numbers and ages.

Then Build a rotation: pick the groups, pick the activities in the order they should rotate, say which day, when it starts, how long each turn lasts and how long a gap between. It makes every session at once. Everybody takes a turn at everything, nobody ends up in two places, and nothing runs twice at once.

It tells you what it is about to do before you press anything — “16 sessions · 4 groups · 4 slots · finishing 14:15”. Sixteen rows appearing with no warning would be a bad surprise even when they are all correct.

More groups than activities is fine. With six groups and four activities, two groups get a free slot each round and over six rounds everybody has still done all four. The alternative would be double-booking the tower, which is worse than a gap in somebody’s afternoon.

Anything that clashes with what is already on the schedule is reported rather than forced. If the tower is already booked at eleven, you get the fourteen of your sixteen that fit and a note naming the two that didn’t — which is more use than refusing the lot and leaving you to work out why.

The numbers are copied onto each session, not linked. Changing a group’s size afterwards does not quietly restate a rota you have already staffed — edit the sessions if you want them to follow.

If the groups don’t add up to the booking’s party size, it says so and lets you carry on — the numbers genuinely do move in the fortnight before a school arrives. Deleting a group never deletes its sessions: they stay on the schedule and become sessions for the whole booking.