Which is the odd one out?

[Leif]

So, which is the odd one out?

and why?

[HansV]

Let's see:

Spoiler

The second shape is the only one without a border.
The third shape is the only circle.
The fourth shape is the only green one.
The fifth shape is the only small one.
So the first shape must be the odd one out.

[Leif]

So you know Tanya, do you?

[HansV]

Huh?

Is this another puzzle?

[Leif]

Spoiler

Tanya Khovanova’s Math Blog » Blog Archive » The Odd One Out
(I believe is the original.)

[HansV]

I honestly didn't know about that - I've never seen that blog. My reasoning really went more or less the way I posted it.

[Leif]

Then you certainly deserve the

[VegasNath]

Spoiler

The first one.

[HansV]

Ooh... how did you guess?

[Reimer]

Strange, I can't see any shapes in the first Post.

[HansV]

The image in the first post is hosted on another site (http://www.tanyakhovanova.com" onclick="window.open(this.href);return false;), perhaps that site is blocked for you?

[Reimer]

Probably. I am at work.