Display half a simple symmetrical house beside a vertical line on the IWB as pupils settle. Take three hands-up answers, not open call-outs. Do not draw the second half yet, that is the work of the lesson.

Each display tool shows both halves at once and statically: the prefilled half on one side and its finished reflection already mirrored across the line. Nothing animates or appears on tap, so trace the counting with your finger square by square rather than waiting for a reveal.

• L-shape — point to each shaded square, count its distance from the line aloud, then ask a pupil to name where the match sits before you point to it.
• Staircase — stress that the steps reverse direction in the mirror; turn-and-name to a pupil: 'tell me how many squares this step is from the line'.
• Arrow — ask 'which way does it point now?' and take two hands-up answers before pointing to the reflection.
• Tree — note the trunk sits right against the line, so its match sits right against it too; revoice a pupil's distance count back to the class.

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.

Start with the four squares already seeded. Invite a pupil to shade one matching square; the class checks the distance from the line is equal before moving to the next. Once that picture is complete, clear the board, seed one new small pattern of your own, and run it the same way with a different volunteer. Two pictures with class checking comfortably fills the time. Watch for the common slip of counting from the edge of the grid instead of from the mirror line — head it off by always returning to the line first.

This round is the practice bank — pupils take turns at the board, check each answer, and the class confirms before moving on. Keep the board work brisk rather than over-explaining.

Pause on the picture that touches the line: ask whether the square on the line moves or stays put. On the final challenge, swap to a horizontal mirror line so pupils transfer the same counting idea up and down rather than left and right.

Recap by asking one pupil to say, in their own words, how to find where a matching square goes.