Agile product development and rapid prototyping

1. a) Explain what a prototype is and what it is used for.
2. b) Propose an example of a cheap prototype for each of these three projects: a note-taking app, a new juice flavour, and a trade fair booth.

Why is it said that the first prototype should be "quick and cheap"? Explain what two things are sought with it (learning early, spending little) and what is lost if the first prototype costs $100\ \text{€}$ and takes two months of work.

Explain what 'failing fast and cheap' means and why it is a smart strategy and not a surrender. Give an example of a failure costing $2\ \text{€}$ and one afternoon that can save $50\ \text{€}$ and two weeks at a fair stall.

The figure shows the agile development cycle: four stages that repeat over and over again, but one is covered with a question mark.

1. a) State which stage is missing between the idea and testing, and explain what is built in it and with what materials in a school project.
2. b) Go through the cycle twice using an example: a bracelet stall that changes its design after the first test.

Define what an iteration is and what is learned in each round of the create → test → learn cycle. Illustrate it with the recipe for the school market biscuits: describe what the team changed (or would change) between the first and the second batch.

A wooden keyring evolves as follows: version $1$, an engraved rectangle; version $2$, with rounded edges because it poked into pockets; version $3$, with the school name in colour because customers requested it. Explain what the team learned in each iteration, how they found out, and why they did not design version $3$ directly.

The "minimum viable product" is the simplest version that allows you to start learning from users. Define what the minimum viable product of a juice stall would be: what you would include (two flavours, a single size, cash payment) and what you would leave out of the first version (an extensive menu, food containers, app orders), justifying each exclusion.

Define the minimum viable product of a 'board game hire service at break times': what you would include in the first week (three games, a sign, a loans notebook) and what you deliberately leave out (a membership fee, an app, $20$ games). Justify each exclusion with what is learned without it.

Plan the first three iterations of the 'school recycling point' (collection of batteries and old phones): v1, a shoebox and a sign in a single class; v2, three boxes with improved signage after what was learned; v3, a fixed monthly point with weighing and a results board. For each version state which hypothesis it tests (do people bring batteries if the point is nearby?, does the signage change behaviour?) and which metric you would use.

One fair team wants 'the perfect stand' and has spent $3$ weeks building it without selling anything yet. Another team sold $20$ badges in the first week with a paper sign and learned which models sell out. Compare both with the language of the topic: which cycle each one follows, what each one is learning and what the 'perfect' team risks on the day of the fair.

Your team lists six features for the breakfast stall prototype: a menu with $6$ items, pre-orders, card payment, a stamp loyalty card, stall decoration, and delivery to the classroom. You only have $4$ weeks and two people.

1. a) Prioritise: which two features make it into the first prototype and which are left out, using explicit criteria (what is learned with each one and how much it costs).
2. b) Defend why "including everything" would turn the prototype into a delayed product, and what you would say to the teammate who insists that "something would be missing".

Your team has $3$ weeks and a list of $8$ improvements for the breakfast stall: a wider menu, advance orders, two tills, decoration, a loyalty stamp card, coffee for teachers, compostable wrappers and a product photo on the sign.

1. a) Prioritise the improvements with an impact/effort matrix: place each one and choose the three that go into the next iteration, justifying the criterion.
2. b) Explain how you will present the five discarded ones to the team (they stay in the 'car park', they are re-evaluated after the fair) and why knowing how to say 'not yet' is the core skill of agile development.