Position. How fast position changes is velocity. How fast velocity changes is acceleration. How fast acceleration changes is... jerk. Then snap, crackle, and pop.
Here it is explained:
So each one is a measure of how fast the previous one is going. Position is the location of your car, velocity is the speed of your car, acceleration is how hard you have the foot on the gas. jerk is how fast your foot is moving on the accelerator, snap is how fast your foot is accelerating on the accelerator. It can be conceptually visualized as the pedal controlling the thing you're looking at as you just keep repeating it.
The thing is that large variations in 'snap' can be visible as "unnatural" or "uncanny" ... A very consistent 'snap', even when "jerk" is strongly controlled, can make things feel overly precise or planned. Imagine someone "doing the robot dance"
Scientifically accurate images of Earth's sky with Saturn's rings taking into account shadows and latitudes.
I was getting the tube back home the other day, just after sunset -- the sky was burnt umber, all deep orange and brown and shadowed. And because it was late, it was dim, that low light where it's not bright and not dark, but the clouds look painted on horizon, unlit. But so, yeah, it looked like a gas giant, a planet just hanging there.
And I thought... Well, Nasa have their Pluto time widget which tells you at what time of day it's the same brightness as it is around Pluto, for where you are. So I worked it out for Jupiter, where it's about 1/27th as bright as Earth -- which, it turns out, for London, on a winter's evening, is about 6pm.
So by coincidence, that day in the late afternoon, I was looking out at a sunset with the colours and pattern of Jupiter, just as bright as Jupiter itself would look, if I was hanging by it in orbit, gazing across its deep clouds and churning storms.
Back in 2007, it used to be that tech startups were old Unix tools warmed over for the Web. grep is Google. finger is Facebook.
Then there was an era where tech startups were about individuals doing stuff publicly. YouTube, blogging, Twitter.
I think there's a similar, simple pattern now: There are a ton of big startups aimed at doing stuff your parents used to do for you.
Uber is being carted around. On-demand laundry and odd jobs is about having someone pick up after you. Food delivery is about being cooked for.
And with the re-emergence of artificial intelligence (only this time with a buddy-style user interface that actually works), this question of "doing something for me" vs "allowing me to do even more" is going to get even more pronounced. Both are effective, but the first sucks... or at least, it sucks according to my own personal politics, because I regard individual alienation from society and complex systems as one of the huge threats in the 21st century.
This user experience "stance" is similar to the dichotomy we see in Internet of Things consumer products: Is it me controlling the product with my smartphone, or does the product have smarts of its own? I favour the second. There are a lot of smart home gadgets that you need a phone to control. Fine.
But when you use Sonos speakers you find that they connect to the streaming music services across the Internet themselves. You ask the speaker to "tune in" to music using your phone. Then somebody else can use their phone to adjust the track, change the album, whatever.
The difference between these two stances sounds minuscule and academic... but one approach leaves the product diminished, no more than a physically rendered version of an app. And the Sonos approach allows the speaker to stand alone, and consequentially become more social and more part of the home.
I don't know how to refer to this design challenge (in Internet of Things, in artificial intelligence) except as stance. There must be a better way of talking about it.
Some more imagery...
Geometrica, patterns by Guy Moorhouse.