Recycle Logo
Gary Dean Anderson designed one of the most recognizable icons in all of history. He created the recycle logo. I think it’s brilliant.

It was created in 1970 by Anderson (then a 23 year old student at the University of Southern California), and he was award a prize for his design of $2,000, bestowed on the very first Earth Day.

The logo has always appealed to me because it is both simple and complex. It reminds me of the Penrose stairs from the Escher print Ascending and Descending.

The logo design depicts what mathematicians call a Möbius strip. A Mobius strip is a surface with just one side. If you join each of the arrows to the tail of the next one you form a band that has just one-half twist in it. Brilliant. Pure. Elegant.

You probably played with Mobius strips at school, and experimented with cutting them in half.
Imposter
However, as you look around, you might find a doppelgänger recycle symbol in common use. Here is a picture of this ‘imposter’:

Notice the difference?
You could be mistaken for not noticing the difference, it’s subtle.
It’s easier to see when you place the symbols side-by-side. Now can you spot the difference?

The ‘fake’ uses three identical arrows, each rotated around 120°. If you attach each arrow to the tail of the next one you get a band with three half twists (not a simple Mobius strip with a single half-twist).
It’s easy to see why the fake one is so commonly used. It’s much easier to construct using just one arrow and a couple of rotations. In the imposter variant, all the arrows ‘bend’ the same way.
I’m calling the imposter a fake, but that is disingenuous. The recycle symbol is in public domain. It is Copyright and Trademark free. There is nobody owning it to give any design guidelines. There is no correct way to render it.
Interestingly, whilst the symbol is in public domain, and there is nobody to tell you that you have it right or wrong, if you attempt to use any variant or stylized alternative of the logo on your product, inappropriately, you will get into a lot of trouble by the FTC (or your own local equivalent) for a deceptive practice. All variants of the logo convey the same meaning, and it is not be be abused.
Unicode
Recycle symbols are in such common use that they are included in the Unicode specification. Below are the appropriate symbols and their codes. Depending on the support of your browser these may, or may not, render correctly.
U+2672 ♲ UNIVERSAL RECYCLING SYMBOL
U+267a ♺ RECYCLING SYMBOL FOR GENERIC MATERIALS
U+267b ♻ BLACK UNIVERSAL RECYCLING SYMBOL
U+267c ♼ RECYCLED PAPER SYMBOL
U+267d ♽ PARTIALLY-RECYCLED PAPER SYMBOL
It’s interesting to note that the Unicode standards people went with the fake design.
Update
Shortly after publishing this article, I was contacted by Amit Patel, creator of the epically brilliant blog Red Blob Games referencing me the article on https://emojipedia.org/recycling-symbol/ about the recycle symbol and how it is rendered in various clients and their interpretations of what 'black' means in respect to the original unicode concept which was to render it in complement contrast. It's fascinating to see how different teams implemented the symbol, the smorgasbord of designs, and yes, the mixture of 'real' and 'fake' variants in the designs.

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Does it matter?
There is something to be said for the rotational symmetry of the surrogate design, it is elegant in its own way. In some ways it is a ‘cleaner’ design with all the arrows bending the same way; I have nothing against it. It’s just that it is not a Mobius strip! (and not the design that won the competition).

I don’t think it matters which variant you use. I just find it interesting that you probably see this logo every day, and undoubtedly never noticed the difference. Until now that is! Now you have read this article you will be cursed with knowledge. Now, for the rest of your life, each time you see a recycle logo, you will mentally rotate the arrows to see which of the variants is rendered.
You are welcome!