Only another reflection undoes a reflection
The Short Answer
A reflection flips a figure across a line, producing a mirror image. It is not a rotation and it can never be undone by one: no amount of turning will put a reflected figure back. Every point ends up the same distance from the mirror line on the other side, and the order in which features run round the outline is reversed.
What a reflection is, and what it is not
A reflection flips a figure across a line. Every point ends up the same distance from that line as it started, on the opposite side.
A rotation turns a figure about a point.
They are not variations on one another, and the difference has a consequence worth saying out loud because it settles most of these questions:
No amount of turning will ever undo a reflection. Only another reflection will.
The hands test
Hold up both hands. Same shape, same size, same fingers.
Now turn one so it matches the other exactly. You cannot — and no amount of trying will help, because one is the mirror image of the other.
That is the whole idea, and most children find it more convincing than any diagram.
The order test
At exam speed, the eye cannot tell a flip from a turn. So don't ask the eye.
Put a finger on one feature and travel round the outline in one direction, naming what you pass: the long side, the step, the point, the notch.
Now do exactly the same on the figure you are checking, travelling the same way.
Same order — it was turned. Reversed order — it was flipped.
This test never fails, which is unusual, and it is worth teaching as a routine rather than as a fallback.
Where the mirror line is
The line matters as much as the flip.
Every point stays the same distance from the line, on the other side. A figure sitting close to the line stays close; a figure well away from it lands well away on the far side.
A common wrong option is the right shape reflected across the wrong line — the flip is perfect and the position is not. It survives any check that only asks is it a mirror image?
Symmetrical figures hide the difference
On a symmetrical figure, a reflection and a half turn give exactly the same result.
Which means a child can answer these correctly for the wrong reason, repeatedly, and build a habit that has never been tested. The paper then uses an asymmetric figure, where the two are completely different, and the habit costs the mark.
Where do pupils lose marks?
Choosing a rotation when the question asked for a reflection, or the reverse.
Reflecting across the wrong line, so the shape is right and the place is wrong.
Judging by overall appearance rather than by a specific feature.
Assuming symmetry, and never noticing that the figure in front of them isn't.
How can we practise this at home?
Tracing paper, and about three minutes. Draw a lopsided shape, trace it, and flip the tracing over — that is a reflection, and turning the tracing without lifting it is a rotation. Children who do this once tend not to confuse the two again.
Then the version with no equipment: draw a shape, hold it up to a window, and look from the other side.
Free: a Non-Verbal Reasoning workbook
Questions across the Non-Verbal Reasoning question types, with the method printed at the top and full answers at the back. One workbook for the whole strand, not a sheet per question type.
Frequently Asked Questions
How do you tell a reflection from a rotation?
Put a finger on one feature and travel round the outline in one direction, naming what you pass. Do exactly the same on the figure you are checking, travelling the same way. Same order means it was turned. Reversed order means it was flipped. The test never fails, and judging by eye almost always does at exam speed.
Why can't a reflection be undone by turning?
Because reflecting reverses the order features run in, and turning never does. It is the same reason your left hand will never match your right however you rotate it: same shape, same size, and never superimposable. Only a second reflection restores the original order.
Where is the mirror line, and does it matter?
It matters entirely. Every point of the figure ends up the same distance from the line as it started, on the opposite side, so a figure close to the line stays close and a figure far away lands far away on the other side. A common wrong option is the right shape reflected across the wrong line — the reflection is correct and the position is not.
Why do symmetrical figures cause trouble?
Because on a symmetrical figure a reflection and a half turn give exactly the same result, so a child can get the question right for the wrong reason, repeatedly, and form a habit. The paper then uses an asymmetric figure, where the two are completely different, and the habit costs the mark. It is worth practising on figures that are deliberately lopsided.
Sources
- GL Assessment — 11+ familiarisation materials and question type descriptions Published 2025.
- Clever Clogs Academy — our own Year 4 and Year 5 lesson records, Winslow Published September 2025 to July 2026.
We are not affiliated with, endorsed by or connected to GL Assessment or Buckinghamshire Council. Test arrangements change; always check the council's own pages for the current year's dates.
We Teach This Method Every Week in Winslow
Groups of no more than six pupils with two qualified teachers, in person or online. Come and see a session before you decide.