You might run at the sight of a spider creeping up your wall, but if you stop to study its movement, each leg corresponds with another. This makes a spider's movement quite fluid, despite the eight legs it has to control. In leggy robots, there are lots of ways to replicate the movement, but here's a great example using Raspberry Pi.
Kevin Ochs's robotic spider is named Charlotte ( get it?), and it uses a Raspberry Pi and a whole lot of math to get the movement just right. The Raspberry Pi computer sits in between a Trossen PhantomX MKII hexapod body, and the build features some custom C++ coding to work its magic.
With all this coding, it's possible Charlotte can access a few standard math libraries to work out how to move about. Kevin has a remote control, too so he can guide the bot around.
Although it's a little slow, the robot is actually well balanced as it slinks around the floor. There's almost something a bit menacing about Charlotte's gait, just like a real spider...
[And yes, we know; it technically isn't a spider since it only has six legs. --Ed.]