Cover lesson · Drama · Year 8 · Intermediate

Algorithm for a stage change

DCF: Data and computational thinking → Problem-solving and modelling

Name: Class: Date:

Cover teacher — you need no subject knowledge, no computers and no stage

Print: this sheet, one per pupil. Everything needed — the set lists, the timings and the rules — is printed on it. Pupils work alone for the planning and in pairs for the dry run. No computers and no drama space required. This is arithmetic and logic done with a pen.

Run: 5 min read the brief and the two set lists · 10 min work out which jobs can happen at the same time · 15 min write the algorithm in the timing table · 8 min add your IF and your REPEAT · 10 min swap sheets and dry-run your partner's algorithm, ticking or breaking each step · 2 min write your one fix.

Collect: this sheet from every pupil. The dry-run column, completed in somebody else's handwriting, is the part that shows the algorithm was actually tested.

What you are doing

A scene change is an algorithm: a set of instructions, in order, carried out by four people at once, that must finish inside a fixed time. You are going to write one for a real 90-second blackout, work out what can run in parallel, handle the thing that might go wrong, and then have a partner run it step by step to see if it breaks.

The brief

Scene 1 is Nan's kitchen. Scene 2 is a hospital waiting room. The blackout between them is 90 seconds of music and nothing else. You have four crew: A, B, C and D.

Rules

No more than two people in the upstage doorway at the same time.
Things being struck go off through the upstage door or the stage-right wing. Things being set come on from the stage-left wing.
The kitchen table and the vending-machine flat each need two people. Everything else is a one-person job.
Nothing can be set in a position until whatever was there has been struck.

Strike list (Scene 1 out)

Job	People	Time	Route
Kitchen table	2	12 s	Upstage door
Four kitchen chairs (4 s each)	1	16 s	Stage-right wing
Rug (roll, then carry)	1	8 s	Upstage door
Kitchen props: kettle, mugs, tablecloth	1	8 s	Stage-right wing, into the prop box

Setting list (Scene 2 in)

Job	People	Time	Notes
Vending-machine flat	2	20 s	Goes where the kitchen table was
Chair stack (3 chairs) — two stacks exist	1 per stack	10 s per stack	Carried on from stage left
Aligning 3 chairs to the tape marks (2 s each)	1	6 s per stack	Repeat for every chair in the stack
Noticeboard, hung on the flat	1	8 s	The flat must be standing first
Water cooler	1	6 s	Downstage of the flat
Magazines and the "Please wait to be called" sign	1	6 s

The thing that might go wrong

The kitchen table has cleared the upstage doorway in rehearsal, but only just. If it does not clear it tonight, the legs fold — which costs 10 extra seconds. Your algorithm must say what happens in both cases. Do not simply hope.

Step by step

5 min — Read the brief and both lists. Circle every job that needs two people.
10 min — Work out the dependencies: write next to each setting job what must be struck or set first.
15 min — Fill in the timing table. Each crew member gets a column; write start and finish seconds for every job.
8 min — Write your IF statement for the table legs and your REPEAT statement for the chairs in the boxes below.
10 min — Swap with a partner. Read their algorithm one step at a time and complete the dry-run table. Break it if you can.
2 min — Write the one change you would make after the dry run.

Timing table

Seconds	Crew A	Crew B	Crew C	Crew D
0–10
10–20
20–30
30–40
40–50
50–60
60–90

Total time my change takes: __________ seconds. Seconds to spare out of 90: __________

My IF statement

My REPEAT statement

Dry run — completed by my partner

Step I read out	Works?	If it breaks, what breaks

The one change I would make after the dry run:

Success criteria

I broke the change down into jobs and worked out which ones depend on another job finishing first.
I used the four crew in parallel, so the total time is much less than the sum of all the jobs.
My algorithm handles the table-leg problem with an IF, giving an instruction for both outcomes.
I used a REPEAT for the chairs rather than writing the same instruction out six times.
I tested my algorithm by having somebody else follow it exactly, and I recorded what they found.

If you finish early

Rewrite your algorithm for three crew instead of four. What is the shortest the change can now be, and what is the bottleneck?
Add a second IF: the vending-machine flat sometimes will not stand up without a brace. Where does it belong, and who fetches the brace?
Write the reverse algorithm — waiting room back to kitchen — and say which jobs are simply the same steps backwards and which are not.