Here are two shapes made from Lego. What’s the same? What’s different?
![Two rectangles made from 2 by 2 lego bricks. The top rectangle is 7 by 5 and is red round the outside with a 5 by 3 yellow interior. The bottom rectangle is 9 by 3 and is red round the outside with a 7 by 1 yellow interior.](https://alisonkiddle.co.uk/wp-content/uploads/2023/08/Lego23-1024x1024.jpg)
Both shapes use 20 red bricks to make the border.
What other shapes can you make with a border made from 20 red bricks?
How many yellow bricks would you need to fill in the interior of your shapes?