In high school, you probably learned that trigonometric functions – like sine, cosine and tangent –can be derived, geometrically, from a circle (hence why trig functions are also known as "circular" functions). But what happens if you use a square to derive these functions, instead? Or a triangle? Or a heart?

Kasia Jackowska's Drawing Mathematics series takes an unusually adorable approach to illustrating mathematical concepts. The Pythagorean Theorem and Sierpinski triangles are conveyed through drawings of elephants, snakes, and deer.

Really loving this series of minimalist math posters by graphic designer Hydrogene.

Having a strong opinion about an issue can make it hard to take in new information about it, or to consider other options when they're presented. Thankfully, there’s an old rule that can help us avoid this problem — and even help us make good decisions when we’re uncertain. Here’s how Bayesian Reasoning works, and why…

WolframAlpha has compiled a growing list of portraits of iconic figures drawn by parametric functions. Some of them are surprisingly good – though, as Joe Hanson points out, there's a decent chance these functions are being churned out by a computer instead of an actual person, seeing as they are OBSCENELY complex. (

Here are two things you should do immediately. One: watch this. It's a jaw-dropping video of starlings in flight that will straight up give you chills. The swirling cloud of birds is called a "murmuration," and it's just one example of how animals in very large groups can engage in remarkably coordinated collective…

We may be celebrating Pi Day here at io9, but we would be irrational to deny that there’s more to mathematical interestingness than simply dividing an object’s circumference by its diameter. Here are seven numbers we love as much as pi.

A recent still from Star Trek: Into Darkness shows Benedict Cumberbatch surrounded by redshirts. This, we surmised, could only mean one thing. Anyone with a hint of SF-savvy knows that the grisly fate of a Starfleet crew member clad in crimson is as certain as Cumbermouth's tubercle is sharply defined; in the Star Trek …

This is excellent. Last night a friend sent us this post by redditor TheIndieArmy, who observes that "the popularity graph for the name Bruce looks awfully familiar."

We say "almost," because like many of the bets in Richard Wiseman's earlier bar-trick videos, a few of these are liable to get you punched in the face. (I'm looking at you, #4. Ten to ten? Really?)