Is that art Escher style or Alhambra style?
The Two Kinds of Tessellation

Tessellations can be divided into two groups: those which are pictures of "real things" like people, pencils, housepets, and piranhas... and those which aren't.

That first kind is ofen called Escher-style tessellation, or "representational art" tessellation. In that kind of tessellation, each "tile"-- each repeating shape-- looks like a real thing. Escher didn't invent that kind, but he did reinvent it and popularized it in Western culture.

The other kind of tessellation is much, much older and more widespread. It's often called geometric tessellation, or Islamic tessellation, or Alhambra style, or non-representational tessellation. The earliest tessellations were simple stone paths and brick walls. In Roman times, tessellations often made pictures, but the pictures were made of colored simple square tiles. The pictures were groups of colored tiles, not individual tiles shaped like fish or fishhooks or fishermen.

It's worth noting that Escher, the most famous tessellator of tiles shaped like "real things", drew his inspiration from the other kind of tessellation. He saw geometric tessellations in chemistry, geography and biology. He also drew heavy inspiration from an Islamic-style palace called "Alhambra", in Granada, Spain. The decorative tessellations of Alhambra are very beautiful...even awe-inspiring... to artists and mathematicians.

For simplicity's sake, let's call the two kinds of tessellation "Escher style" and "Alhambra style", though we could just as rightly call them "representational" and "abstract", or "things" and "geometric shapes", or "non-Islamic style" and "Islamic style".

The original webmaster of Tessellations.org, David Annal, preferred to post only Escher-style tessellations. I think he felt, as I do, that tessellations which look like "real things" such as people, cats, and toasters require the artist to do a lot of tweaking of the tile shape, proof that the artist invested time and thought, and had a goal-- a theme-- in mind. Simply geometric or abstract designs have no such requirement, and so (David thought) they might require less effort from the artist. If your tile shape looks like a random blob or a piece of chicken wire, how can I know that you worked hard on it to make it look juuuuust right?

However, I've had a change of heart. Two years ago a Muslim person wrote to me from the Mid-east, asking why my site didn't show Alhambra style tessellations. He reminded me that

• Islamic-type tessellations predate Escher's type-- in fact, the ones at Alhambra inspired Escher.
• Islamic-type (geometric) tessellations are, when done ...ummm... artfully, are quite beautiful in their own way.
• It'd be a little unfair...even ...what's the word I'm looking for?... possible religous bigotry, were I not to accept art simply because the artist's religion insists that its artists never portray "real things".

Some religions, particularly in the Judaism-Christianity-Islam line, prohibit portraying images of "real things" for the simple reason that those images become something people might worship (like the golden calf in the torah/bible/koran) instead of that religion's god. The art might become an idol. When you see how much the painting of Mona Lisa or the Statue of Liberty or the ceiling of the Sistene Chapel earn peoples' awe, you can sort of see the point.

Without entering a religious debate, it's worth noting that Islamic artists often obey the letter of that law, but not its spirit: some Islamic calligraphy is shaped like real things... like horses, for example... and although the alhambra's geometric art is not "real things"-- not representational art, that is-- it's so beautiful as geometry and math interwoven, that the resulting abstract art is as awe-inspiring and attention-grabbing as the painting of Mona Lisa.

So, I've eased away from David Annal's initial strict prohibition against Tessellations.org showing geometric/Islamic/Alhambra/non-representational art, but I *do* insist that any of that other kind of tessellation be of a high grade, showing high artistic value and that an effort has been made to tweak the outlines for some artistic reason.

For example, if the whole tile seems to be a mostly organic (swoopy, curly, no-straight-lines)shape then it shouldn't show its original "corners" or walls-- observers shouldn't be able to quickly guess, or see leftovers of, the simple geometric "cell" (the geometric shape that the tessellation started as). The original tessellation shape's flat lines atnd sharp corners shouldn't be visible in, say, an organic, swoopy style that the artist is aiming for. Put simply, the artist should show that s/he's not being lazy, and that s/he is tweaking the tiles toward some definite artistic goal. If it looks like a meaningless, flavorless blob or just a minor tweaking of a simple geometric shape, I won't be impressed.

For an example in the other direction entirely, if a tessellation is all sharp corners and recognizable geometric shapes like stars, diamonds, and triangles then the artist had darned well better be showing me something awesome, not something that looks as been-there-done-that as institutional masonry or chicken wire.

So: would I post some abstract tessellations from guest artists on Tessellations.org? Sure... but they'll have to be of a high standard and in some way "move" the observer: it should inspire awe or fascination or some other emotion. My criteria for non-representational tessellation are a bit vague, but I hope I've given you some sort of guide so you can predict which art I'll want to accept.