Summer of Math Exposition

Minor constructive feedback:

Sentence redundancies (13 min) - ” it’s not to hard to PROVE this from the special case we just PROVED” followed by “so ill leave that as a challenge video” the challenge needs clarity.

(6:28) - unnecesary redundancy & changes the pace. when you speak, try to wave your arms less; it’s a sign of nervousness. You speak well, have confidance.

Title: “but why are triangles the strongest?” I thought this was gonna be a video about throwing things at different shapes and seeing how they handle it. That there might be some visuals on compression and tension of the triangle.

added great clarity with the equasions and multi colored rotation meters

1-9 Motivation: 1 Clarity: 9 Novelty: 2 Memorability: 2 14/4 = 3.5 out of 9

I feel voting based on these criteria is unfair; for this video in particular, it was a really great video!

omg, subtitle is fantastic, it move up when otherwise it will block the text, and it even has color. but some of them is indeed too long.

Even if I’m originally not interested in this topic, I still learn a lot through out the video

Very well explained with nice and informative visuals. I’ve lost in the last half of the video a bit since it was my first time on the topic.

Really fun, really understandable.

I learned something very scary and challenging in a way no engineering book explained it. I’m sure there is way more to calculating degrees of freedom than what is in this video, but now I might be able to learn that if I ever want to.

The two problems with this video are that the author puts the equation for degrees of freedom of a convex three dimensional shape near the bottom of the screen where it gets squished and hard to read. And he could slow up his delivery a bit. But all in all a great video.

Pretty interesting ideas, I didn’t know what to expect but this is a pleasant video. Could maybe have more elements in the visuals to reduce some space.

The explanation of convex versus concave was well done, both the script and the visual animation. I was also really impressed by the light stereopgraph? projection, very cool! I don’t think I left the video thinking about how strong triangles are, but more about how complex rigidity can be. I think degrees of freedom is a really interesting concept that people don’t get exposed to outside technical jobs and like CAD so I really enjoyed this as a gateway to that.

Visuals were great I liked how it was broken up between the graphics/animations and real life felt very human.

Thanks for this informative video :) Your video was interesting to watch and easy to understand. The switch between animations and camera view was well-balanced. I especially liked that you demonstrated some concepts on real-world objects such as the legos in the beginning. The pacing of the video was also good, and the breaks to think about one’s own solution were well-timed.

Your camera presence is relaxed and natural. My favorite part was when you explained how you unwrapped the 3d sphere to a 2d plane, very cool! Your examples followed a clear logic and were just the right level of difficulty.

There are some small things that could’ve elevated this video. These may also be interesting for your future videos.

• Audio: An audio filter may boost clarity and reduce noise in the voiceover parts.

• Colors: Your animations have a “basic manim” feel due to the black background and standard colors. A custom background (color) + a custom color scheme + a different font could set you apart from other channels and make you look more professional. This should be easy to implement in your manim code.

• Thumbnail: The thumbnail is hiding how interesting this video is. How about showing your face, the lego and a cool triangle shape? Then it could be distinguished from low-quality AI videos.

• More real-world examples: There should be many real-world examples of constructions with triangles. For example, I immediately thought of radomes, the Eiffel tower and pyramids. If you showed some examples at the beginning, it could help improve the retention rate (and also make a more catchy title such as “Why do the most stable buildings consist of triangles?” or so).

These are just some “polishing” aspects, overall I really enjoyed this video :)

Floppy modes? Oh I know about those. We could format them 720KB or 1.44MB, and we could double format them 2.88MB. And that’s just the 3.5” floppies. That’s a lot of degrees of freedom!

The animations are really good, but I think that the script could use some work. I think you should go a bit slower. Maybe it’s just me, but I had to rewatch parts of the video several times. I liked the part about degrees of freedom at the start, and I liked the natural derivation of the formula 3 * joints - connections = 6. But I found the argument at 7:03 to be very opaque. I also thought your definition of “convex” was a bit strange. The classic explanation that I like to use is the “rubber band test” - there are several youtube videos on this. There are other explanations as well, involving angles. I thought your explanation was fine but I found 9:33 - 11:01 to be a bit confusing. I wasn’t sure what concavity had to do with the larger topic.

Also, this is a nitpick, but I would recommend either not moving your hands, or having more varied hand movement. The repeated hand movement of lifting your hands and then lowering them while keeping your wrists flexed seems a bit distracting (even if it may be natural to you!). Derek from Veritasium is great at this. Alternatively, since your Manim visualizations are so strong, you may want to stick to them entirely for the video, and not record any parts with a camera.

Overall, it was better than average but not fantastic. I look forward to watching your channel in the future!

So great to see small creators entering the SoME5 competition. As I’m writing now, I see that you only have 8 subscribers and this one video. It is clear that you learned a lot of Manim to do all the 3D animations!

I watched your video. I think the clarity of the video varies throughout so I’ll do section by section.

1. Degrees of freedom. Fantastic. I understood it with no problem. In fact I even paused the video to worked out the degrees in your examples.

2. 7:07 Index < 0 with self stress. When I first watched I didn’t quite get it, because I thought the connecting rods are hard rods. They aren’t supposed to stretch and change length like how you animated it. I only understood it later at 14:22. I was like “OK so self stress are the redundant rods you add to an already rigid structure”

3. 7:38 Proof of 2D case. It’s all right. You used words like “sticking-out triangles like this” and “triangles like this”. At first I didn’t understand what those are. I had to convince myself that those were the only two cases. So if you explicitly explained the 2 cases as “triangles sharing 1 border” and “triangles sharing 2 borders” it would be better.

4. Proof of 3D case. My least favourite part. Don’t get me wrong the animations are slick. But when you pull out the triangle at 10:04. Notice that there are 19 coloured regions on screen, not 20. When you do the stereographic projection, the original triangle you pull out is not one of the 19 disjoint triangles, and I felt that should’ve been called out then and there. So at 11:05 when you remove the FIRST triangle, that first triangle is bordered by 3 triangles, not 2. I know you called out “the triangle you got rid of at the start” at 12:34 but I wasn’t not sure if that fixed it, and in any case I really wanted to hear this logic clearly explained.

So overall, if the clarity of the whole video were all like the Degrees of Freedom part this would’ve been at least a 7. But the later parts were less clear for me, and I feel the 3D proof really needs more clarity with how that missing triangle is accounted for.

Great video! The background noise is a little distracting, though.

Found this extremely interesting and engaging. I think it could have benefitted by describing how triangles are used in engineering, e.g. design of bridges - the title assumes the viewer is already familiar with this fact. The video feels slightly advanced for highschool, and it wouldn’t be a stretch to assume the viewer has seen rank-nullity theorem.

Great production quality, including the animations and colored captions (nice attention to detail!)