yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Tangram Paradoxes


less than 1m read
·Nov 10, 2024

I can take the seven pieces of a tangram and arrange them into a shape called the monk, but I can take the same seven pieces and arrange them into a monk with no feet.

Wait, what? Where'd the foot go? How can these be made of the same pieces? Is it magic? No, it's a Tang G Paradox, which is a kind of dissection fallacy.

In my Bonet Tarski video, I showed an example where we fail to notice how the parts have changed, so we're surprised when the whole does. But in this kind, we fail to notice exactly how the whole has changed, so we're surprised to find that the parts haven't.

Illusions like these are caused by the fact that a concentrated area of missing material is much more noticeable than an equal but diffused increase everywhere else that compensates for it.

Both of these figures have the same area. The one with no feet has a slightly larger body, but the area of just the feet spread out amongst an entire arrangement... well, it's kind of hard to see.

Sometimes the things we don't notice can be quite significant.

More Articles

View All
Khan Academy view of mastery learning
The terms mastery learning are used a lot these days, but I want to do a video on them because they can mean different things to different people. I want to talk about what it means, at least in a Khan Academy context. So to give us some perspective, let…
How to Stop Wasting Time on the Internet - 4 Awesome Tips
[Music] If you’re watching this video, there’s a pretty good chance that you shouldn’t be watching it and should be doing something more productive instead. But if you’ve already done your work, good for you! Either way, here are four useful strategies yo…
Factoring completely with a common factor | Algebra 1 | Khan Academy
So let’s see if we can try to factor the following expression completely. So factor this completely. Pause the video and have a go at that. All right, now let’s work through this together. The way that I like to think about it is I first try to see if th…
Fractions greater than 1 on the number line
We’re asked to move the dot to 7⁄6 on the number line, so pause this video. I can move this dot right over here, but I encourage you: pause the video and put your finger on where 7⁄6 would be on the number line. All right, now let’s work on this together…
Representing quantities with vectors | Vectors | Precalculus | Khan Academy
We’re told a powerful magnet is attracting a metal ball on a flat surface. The magnet is pulling the ball at a force of 15 newtons, and the magnet is 20 degrees to the south from the eastward direction relative to the ball. Here are a few vectors where th…
Ben Silbermann at Startup School 2012
Well, first thanks a lot for having me. Um, it’s really exciting for me to be here in front of like so many people that all want to build cool things. I was getting ready for the talk last night, and I was going back through old emails because sometimes …