Lay out (or display) a red-blue-red-blue strip of six pattern blocks as pupils settle. Take three hands-up answers, not open call-outs. Don't confirm the answer yet — the method to be certain is what Watch and Notice will build. Give five seconds of quiet think-time before any hands go up.

Walk each example aloud, one at a time, using the display snapshots.

• Two-shape unit — ring the first triangle-square pair on the board with your finger; say this is the unit, and it keeps coming back. Ask the class to call out the eighth shape and explain how the unit helped.
• Three-shape unit — point to the third, sixth and ninth shapes and say every third shape is blue. This is the key insight the whole lesson rests on, so do not move past it until the class can say it back to you.
• Skipping ahead — with your finger, count along the row in threes (three, six, nine) and land on a blue square each time. Make the point that counting in threes is faster than laying out every block, and that the unit length is the times-table you count in.

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

Start a unit on the pattern-blocks board (e.g. circle, square, triangle), then call an individual pupil up to add two more full repeats and ring the unit. Have the class agree the next shape before the pupil places it. Rotate four pupils across units of length two and three. Watch for the common slip of ringing too many or too few shapes as the unit, that is the moment to revoice where does the pattern start to repeat?

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.

For each target, ask the class first: how does knowing the unit length help us skip ahead? For the twentieth shape of a three-shape unit, model counting in threes on the board (three, six, nine, twelve, fifteen, eighteen) and then stepping the last two on, so pupils see they don't need to lay out twenty shapes. The on-screen Check confirms each one — use the ✓ as part of your narration (yes, that's it).