Oh, come on, no day is complete without the word whiffletree.
Yes, yes, I know it's a term for part of a draft horse's harness, and that few of us go to work in a horse-drawn carriage, but it's still too good a word to ignore.
What is it? Well, it's basically a bar with a ring facing forwards on either end, and another ring in the middle facing backwards.
If you have three horses pulling a load, this is the way you'd link your whiffletrees together:
The idea is that the arrangement evens out the pull that comes first from first one side of the animal and then from the other.
Luckily, if you don't often see a horse pulling a load on your daily commute, then here is a similar arrangement on a more modern form of transport:
See how the windscreen wiper works in just the same way? Neat, huh?
Now, I don't want to leave anyone out, and so this example of a whiffletree-type arrangement is especially for the Martians among you.
These are the wheels of the Mars Pathfinder vehicle:
It's jolly good for bumpy ground - though personally it makes me feel seasick.
Spot the Frippet: whiffletree. This word seems to come from the words whip and tree (in its meaning of a post or bar).