Copyright © University of Cambridge. All rights reserved.

## 'Pattern Recognition' printed from http://nrich.maths.org/

Imagine the big square being filled in one square at a time, column
by column.

How many times does the colour switch on the next square?

How many lines of one colour of different lengths are there?

To see how codes change, try seeing how a small change to a grid
affects the code. Try this

- Press Randomise Grid
- Check Code
- Store Code (this keeps the current code for the grid)
- Now change one of the squares (click on it)
- Press Check Code again.
- The codes for the grid will be displayed side by side. By
looking at how the code has changed you might be able to work out
how the codes were produced

By looking at how the code has changed you might be able to work
out how the codes were produced.

To work out the way a pattern is deemed random, try looking at the
digits in each code string individually.