Symmetry

Butterfly
Courtesy of Wexford County Library

If you look at a picture of a butterfly you will notice that the pattern on one wing is like a reflection of the pattern on the other one. In the same way, one hand looks like the mirror-image of the other one.

Each of these are symmetric around a centre line. The human body is nearly symmetric – the left side looks like a reflection of the right side. If you cut a symmetric picture along its centre line then you can produce the original shape by holding a mirror to one half.

The inside petals of a tulip are also symmetric but not around one centre line. If you cut it into three pieces then you can produce the full shape from one piece by placing it between two mirrors.

Tree
Courtesy of the EPA

Try the same with pictures of other symmetric flowers, trees, starfish etc. It will also work if you cut these pictures into six sectors.

Trees and leaves are usually not perfectly symmetric. Even your hands are not perfectly symmetric; some lines on one hand are not matched by lines on the other one.

Faces too are rarely perfectly symmetric. To explore this you could print a photograph of a face and then cut it along the centre line. Place a mirror along the cut edge of each side.