Spot the Pattern

What's the pattern?

14, 7, 21, 35, 28 → ?

cat, bat, hat, mat → ?

login page, shopping cart, booking form → ?

Pattern recognition is a core human skill — and a core CS skill.

Spotting patterns lets us write one solution that works everywhere.

Your Scenario

Each person in the group gets ONE scenario card.

• Read your card alone
• Write a complete step-by-step algorithm for YOUR scenario
• Don't share with your group yet
• Solve it independently

Share in Your Group

Now share all three algorithms with each other.

• Read each one carefully
• Look for steps that appear in all three
• Fill in the comparison table on the worksheet

What's the same? What's different? What's the common structure?

Write the General Algorithm

Replace specific words with placeholders:

Write ONE algorithm. Test it on all three scenarios.

Test It

Substitute real words back into the general algorithm for each scenario.

Does it work for all three? Note any adjustments needed.

How many lines did writing ONE general solution save vs THREE specific ones?

That's the power of pattern recognition.

Real World

Sorting algorithms work on numbers, names, dates, and more — same algorithm, different data.

Form validation checks email, phone, postcode — same pattern, different fields.

Database queries filter users, products, orders — same template, different tables.

Key Takeaway

Discussion

• Can you think of a fourth scenario that fits the same pattern?
• Is a general algorithm better or worse than a specific one? Why?
• What would happen if every programmer wrote their own specific sort instead of using a general one?