A new 5th class will walk into this room next September. We are going to design a welcome poster for them.

Think about two posters: one that feels balanced and settled, and one that feels a bit off. What is different about the way the shapes are arranged?

Here is the first idea designers use: measuring how much of the page a shape covers.

On screen is a title box that is 6 cm by 5 cm, shown on a 100-square page. How many squares does that box cover? What share of the page is that?

The second idea is rotational symmetry.

On the plan on screen, the same corner shape is drawn once in each of the four corners, each turned a quarter turn around the centre.

The third idea is a tessellating border: copies of a shape fitting edge to edge with no gaps and no overlaps.

Let's work this out together on the board. Our poster page is a 10 by 10 grid, so the whole page is 100 squares.

Here is a lunch survey the new class might see, showing bars for Sandwich, Pasta, Salad and Wrap.

This chart could go on our poster. If you drew it on your grid as a box 5 squares wide and 5 squares tall, how many of our 100 squares would it fill?

Let's bring one more chart up on the board together. This one compares two possible 5th classes, 5A and 5B.

A chart like this could be one element on your poster. If you drew it on your grid as a box 6 squares wide and 5 squares tall, how many of your 100 squares would it fill?