# Four Layers

Can you create more models that follow these rules?

## Problem

This may be used to follow on from *Cubes Here and There*.

Image

Looking at the three models here you may see that they have a lot in common although they are obviously different.

The things that are the same produce the rules.

So the rules are;

$1$/ Each colour stays at the same level in each model.

$2$/ Cubes of the same colour are not separated - they stay together.

$3$/ The numbers of cubes for each colour is fixed at $1, 2, 3$ and $4$.

$4$/ The cubes sit squarely face to face with no twists or slides.

Your challenge is to create more shapes that follow the four rules.

When you have done so, compare them and show similarities and differences.

## Getting Started

Have you checked that your model obeys the rules?

How will you make sure that you don't repeat any?

How will you make sure that you don't repeat any?

## Teachers' Resources

### Why do this problem?

This activity challenges the most able pupils in their spatial awareness abilities. It also enables them to have something before them to explore and compare.### Possible approach

As this is intended for the most able I would suggest printing out the activity and discussing together first of all.You could get started by asking the group to give you instructions to make the second or third model. Then let them produce their creations.

Key questions

Tell me about your shapes.So what have you found when comparing them?

What can you now explore about these?

Possible extension

Pose the question about balance, asking "Does it matter if the model is stable?".You could encourage children to explore models containing an archway/bridge.