# Holey Trimmetry

Symmetry arising from symmetry isn’t surprising. But what about symmetry arising from asymmetry? You can find both among the rep-tiles, which are geometrical shapes that can be completely replaced by smaller copies of themselves. A square is a symmetrical rep-tile. It can be replaced by nine smaller copies of itself:

Rep-9 Square

If you trim the copies so that only five are left, you have a symmetrical seed for a symmetrical fractal:

Fractal cross stage #1

Fractal cross #2

Fractal cross #3

Fractal cross #4

Fractal cross #5

Fractal cross #6

Fractal cross (animated)

Fractal cross (static)

If you trim the copies so that six are left, you have another symmetrical seed for a symmetrical fractal:

Fractal Hex-Ring #1

Fractal Hex-Ring #2

Fractal Hex-Ring #3

Fractal Hex-Ring #4

Fractal Hex-Ring #5

Fractal Hex-Ring #6

Fractal Hex-Ring (animated)

Fractal Hex-Ring (static)

Now here’s an asymmetrical rep-tile, a nonomino or shape created from nine squares joined edge-to-edge:

Nonomino

It can be divided into twelve smaller copies of itself, like this:

Rep-12 Nonomino (discovered by Erich Friedman)

If you trim the copies so that only five are left, you have an asymmetrical seed for a familiar symmetrical fractal:

Fractal cross stage #1

Fractal cross #2

Fractal cross #3

Fractal cross #4

Fractal cross #5

Fractal cross #6

Fractal cross (animated)

Fractal cross (static)

If you trim the copies so that six are left, you have an asymmetrical seed for another familiar symmetrical fractal:

Fractal Hex-Ring #1

Fractal Hex-Ring #2

Fractal Hex-Ring #3

Fractal Hex-Ring #4

Fractal Hex-Ring #5

Fractal Hex-Ring (animated)

Fractal Hex-Ring (static)

Elsewhere other-available: