Look at this design on the board. It was built on a squared grid. Can you spot a reflection, a slide, or a matching half?

Today you become the designer. You will make a secret picture on a grid, then write directions so exact that a classmate could copy it without ever seeing it.

We will look at one shape shown two different ways. First it is reflected, flipped like a mirror. Then it is slid, moved along without turning or flipping. Notice what stays the same each time, and notice how the grid reference changes.

Today we complete a symmetrical house together on the interactive. The mirror line runs straight down the middle, between columns C and D. We only build the left half. When you tap a square, its matching partner appears the same distance away on the right.

Work through the house in this order. Say the grid reference out loud before each tap, letter first.

• Roof: shade B1 and C1.
• Window: shade B2.
• Walls: shade B3, B4, C3 and C4.
• Door: shade C5.

After each tap, check the partner landed the same number of squares from the mirror line. Then read the new grid references together.

This is your design challenge. On your labelled grid you will make a secret picture, then describe it so exactly that a classmate could redraw it.

First watch how a clear set of directions looks. Here is one finished example on the board:

• Start: shade the square at B2.
• Reflect across the mirror line between column C and D. The partner lands at E2.
• Slide the shape three squares right. B2 moves to E2; E2 moves to H2.
• New grid references: E2 and H2.

Notice the order: starting place, what transformation, then the new references. That is the pattern you will use.

Get as far as you can. Even finishing step one is great.

• Shade a small shape and write down the grid reference of every square you used.
• Reflect your shape across a mirror line and write the new grid references.
• Slide your shape three squares to the right and write where it lands.
• Extra: design a symmetrical secret picture, then write directions and grid references clear enough for a classmate to redraw it exactly. Use the same order as the board example: start, transformation, new references.