этот анекдот я слышал в 1983 году
DA RECTIFIER!!!
[THERE IS NOOO FREE ENERGY!]
Q: What's purple and commutes?
A: An abelian grape.
Credits to Cerebus for letting me know this joke.
What do you call an engineer who keeps swapping I's for A's ?
A twit !
A pointless chart:

Edit: Better image withoud jpeg compression artefacts.
A pointless chart:
And some will verify the percentages add up to 100.
And some will verify the percentages add up to 100.
Yes. And how many people do you think have recalculated the limerick from above?
A pointless chart:
More JPEG compression please.
A pointless chart:
And some will verify the percentages add up to 100.
Well, it has to. If it didn't there would be a fraction, and it wouldn't be pointless.
The famous curmudgeon on data display Edward Tufte (professor of that kind of thing at Yale) considered the pie chart the least efficient format of data display.
His best example was a pie chart that showed the relative fractions of two things, which had to add up to 100%.
(The division of a whole into two unequal parts.)
An entire page to illustrate one number.
The Pointless Pie Chart commits another sin against good graphing that nobody has mentioned, it has a 3D effect to it. So, as seemingly approved of by M$ given the options they make so prominent in the office packages, you can brainwash your business meetings with slideshows of charts that don't even measure in screen area or angle as the data requires they ought.
The Pointless Pie Chart commits another sin against good graphing that nobody has mentioned, it has a 3D effect to it. So, as seemingly approved of by M$ given the options they make so prominent in the office packages, you can brainwash your business meetings with slideshows of charts that don't even measure in screen area or angle as the data requires they ought.
If its not 3D its not a pie. Its a wafer.
The Pointless Pie Chart commits another sin against good graphing that nobody has mentioned, it has a 3D effect to it. So, as seemingly approved of by M$ given the options they make so prominent in the office packages, you can brainwash your business meetings with slideshows of charts that don't even measure in screen area or angle as the data requires they ought.
Yeah all the default charts in Office are crap for engineering use and need a lot of massaging and tweaking settings to make them functional rather than just pretty looking.
Every time i use Excel to graph something i have to calm myself down and remind myself that i am using software designed to be used by an accountant or some paper pusher in the marketing department, not an engineer.
Not a joke, unless you consider us humans a joke:
The funny thing about mirrors is that they do not swap anything, not even left and right.
People think it is the mirror that swaps things, when it really is just the definition of left and right that are incompatible with physical reality; their perception and definition of "direction" that demands something gets "swapped". Funky.
For example, if you have a pimple on your nose on the side of the closest door, the pimple will be on that same side in the mirror too.
Another funny thing about mirrors is that they can be made to swap for real, i.e. a concave mirror.
Another funny thing about mirrors is that they can be made to swap for real, i.e. a concave mirror. 
Nope!

The reflection is only swapped when the focal point (or axis) is between the mirror and the observer. Thus, it is the
chosen path for the light that does the "swapping", and not the mirror: just put your eyeball close enough to the mirror, and the "swapping" always disappears.
However, a horizontally concave but vertically flat – somewhat like a cutout from a cylinder inner surface – mirror, when viewed from a suitable distance, does indeed reflect the image around the vertical axis, letting the observer see themselves somewhat like others see them. It only really works at a fixed distance, because further in or out the image aspect ratio will vary.
Cylindrical mirrors themselves have been used in anamorphic art: the mirror is placed on top of an image which is highly stretched, but when viewed through the mirror, the "correct" picture appears.
Another funny thing about mirrors is that they can be made to swap for real, i.e. a concave mirror. 
Nope! 
The reflection is only swapped when the focal point (or axis) is between the mirror and the observer. Thus, it is the chosen path for the light that does the "swapping", and not the mirror: just put your eyeball close enough to the mirror, and the "swapping" always disappears.
However, a horizontally concave but vertically flat – somewhat like a cutout from a cylinder inner surface – mirror, when viewed from a suitable distance, does indeed reflect the image around the vertical axis, letting the observer see themselves somewhat like others see them. It only really works at a fixed distance, because further in or out the image aspect ratio will vary.
Cylindrical mirrors themselves have been used in anamorphic art: the mirror is placed on top of an image which is highly stretched, but when viewed through the mirror, the "correct" picture appears.
Steve Mould explains it all:
https://youtu.be/sP0cwLuEwsw
Yes, mirrors can help with many tricks. One of the funniest is that it is possible to always reflect the light back, at the same direction from where the light came.

I think it is called "corner reflection", the trick with 3 perpendicular plane mirrors.