@Sannesthesia sounds like it doesn't exist anymore?
@avaric3z4 жыл бұрын
Just build one. Not too hard.
@taberbooth92034 жыл бұрын
Those already exist look inside a car
@AlmightyBungus3 жыл бұрын
‘I’m gonna go to bed early tonight’ Me at 2 AM:
@konosxg71783 жыл бұрын
2 AM is early I blame myself and video games xD
@bingus30393 жыл бұрын
You had to call me out like that
@engineergaming97273 жыл бұрын
Yep
@Harder2583 жыл бұрын
Fun fact: it's 2am here
@rauleleazarbarajas12873 жыл бұрын
True
@odd1ty6124 жыл бұрын
This feels like the opening to some detective show where the detective uses his brilliance in physics and engineering to solve paranormal mysteries.
@THEBIGGAME6833 жыл бұрын
Ye but not gay
@lovelaugh72993 жыл бұрын
Sounds like a gay series
@berserker31083 жыл бұрын
All cool 'til "paranormal".
@patstaysuckafreeboss80063 жыл бұрын
That's sounds really gay but it inspired me to write a short story about a gay detective who solves crime using nothing but his full blown utter gayness
@odd1ty6123 жыл бұрын
I'm confused- would it be better if the detective is gay or straight?
@ninjafishbowl76894 жыл бұрын
It's almost 2 am I don't know why I'm here All I know are Mechanical principles part 02
@lanchanoinguyen29144 жыл бұрын
i just watched videos about homemade lathe.I turned a shaft today for making my own.
@engineering_design4 жыл бұрын
I also have the best tutorials on my KZbin channel called Mt Engineering which is on CATIA V5 and solid works, which helps you to make this kind of animations, and many other things.
@joelreuning-scherer37334 жыл бұрын
This is such a mood
@engineering_design4 жыл бұрын
@@joelreuning-scherer3733 I have the best tutorials on my KZbin channel called Mt Engineering which is on CATIA V5 and solid works, which helps you to make this kind of animations, and many other things.
@rousseauchess42494 жыл бұрын
michal mag 02*
@НиколайАнтонов-я8е2 жыл бұрын
That one mechanism with the spiral driving the bigger gear was called a worm gear. Fordson tractors from the 1930s had worm-gear final drives in the drive axles. They moved slowly but had a LOT of torque in the drive wheels. Edit: Fordson was an offshoot of Ford Farming Equipment and the British Ford Motor Company in the UK. The Fordson Model N made in 1934 had a worm-driven axle.
@elric59432 жыл бұрын
Weird that I saw this comment right on the part you were talking about
@Kadlifal2 жыл бұрын
Which one?
@НиколайАнтонов-я8е2 жыл бұрын
@@Kadlifal Try 1:56.
@jeffsaffron56472 жыл бұрын
I remember our Mechanical engineering teacher from high school warning us about this trick question often asked during finals. "What is the minimum possible amount of teeth on a gear?" "People don't know and guessing 6 or 8" "But correct answer is 1, because worm gear is also a gear!" I am never gonna forget that.
@НиколайАнтонов-я8е2 жыл бұрын
@@jeffsaffron5647 That's technically the truth. The thread on a worm gear is actually counted as one big tooth.
@JaredOwen4 жыл бұрын
Sweet video - I really enjoyed this
@domo29154 жыл бұрын
I enjoyed your whole channel
@chicom32134 жыл бұрын
Reported and disliked.
@kevinjati79534 жыл бұрын
Yo jared. What's the next video. Waiting to see your cool animation. Take your time bro I know your video takes time to make but with that quality im not suprised.
@Enzi_Meteori_9024 жыл бұрын
@@chicom3213 why?
@Enzi_Meteori_9024 жыл бұрын
One of my favourite channel's ever wow
@casiopistachio11073 жыл бұрын
I like to imagine some caveman thousands of years ago figuring this out as a thing but not having any clue how to make them
@dannyboy46823 жыл бұрын
Ancient gears are really interesting. You see contraptions where the gear teeth are wooden pegs instead of spikes
@-w-.3 жыл бұрын
Until one day, a caveman named Alborg Ainstone had a brilliant idea......
@thedemolitionsexpertsledge55522 жыл бұрын
@@-w-. “Why afraid of fire?” He thought, stroking his impressive unkempt beard. “Why not USE fire?”
@MicahThomason Жыл бұрын
Caveman, hell. I've been doing that myself for years.
@Tommy_007 Жыл бұрын
Cavewoman?
@idedary4 жыл бұрын
Most of it lego taught you as kid. I'm proud.
@engineering_design4 жыл бұрын
I also have the best tutorials on my KZbin channel called Mt Engineering which is on CATIA and solid works, stress analysis, motion analysis, part drawings, assembly drawings.
@swampratt364 жыл бұрын
Spirograph 🤣
@kabra57834 жыл бұрын
la cara de maeve XD
@lukasraabe71744 жыл бұрын
Yeah LEGO best toy ever
@modellbaupur21424 жыл бұрын
Yeah
@HeyLoiss3 жыл бұрын
*Minecraft redstone mechanisms are still more complicated to me that this, what the fuck.*
@xPhantom_404x3 жыл бұрын
Same
@traister1013 жыл бұрын
Redstone is just on or off though it sure can get complicated
@traister1013 жыл бұрын
@@Elipsyclips Ah I loved that dude, only mc KZbinr I watch nowadays is Etho
@somedudes64553 жыл бұрын
@@traister101 well i mean, computers are the same as well.
@traister1013 жыл бұрын
@@somedudes6455 Yep, you just stack so many "on or offs" that you got computers.
@welcometoreality4372 жыл бұрын
Once you work with mechanical systems you can truly appreciate how some of these work and are incredibly genius inventions.
@nottherealpaulsmith3 жыл бұрын
1:25 ah yes, i know what these are 1:31 HEY HOLD ON A SECOND
@anderstermansen1303 жыл бұрын
Straight cut gears and helical gears. The next is double helical or herringbone gears.
@frlfrl20983 жыл бұрын
Anders Termansen What's the purpose of helical gears??
@anderstermansen1303 жыл бұрын
@@frlfrl2098 same as straight cut gears but more compact
@vampata3 жыл бұрын
FrlFrl smoother transmission, the teeth stay engaged for a longer time and aren’t released abruptly like in normal gears
@thatguythatguye73193 жыл бұрын
@@vampata less likely to slip as well
@WanganTunedKeiCar4 жыл бұрын
Even the relationship between these gears and other mechanical-term-named things is still a better love story than twilight.
@leichtgesalzener-kabeljaurogge4 жыл бұрын
what a stretch but i like how the gears run in your head
@FifinatorKlon4 жыл бұрын
How is it that I still read garbage memes like this in CY+4 but Arrow to the knee died in 2012?
@Heisenberg-so9vj4 жыл бұрын
Or the Star Wars sequels
@summushieremiasclarkson47004 жыл бұрын
At the risk of analysing a meme, the relationship between these gears is engineered to be perfect, making it better than 100% of imperfect human relationships, which is all of them.
@WanganTunedKeiCar4 жыл бұрын
@@summushieremiasclarkson4700 Good God! That's genius!
@anon_acc4 жыл бұрын
Teacher: „The test is not going to be that complicated.“ The test: 2:14
@codemonster84434 жыл бұрын
This is a drive shaft with an extra hinge. Look below a car, it connects them engine andreal wheels.
@anon_acc4 жыл бұрын
@@codemonster8443 Okay, thanks.
@YEN_calisthenics4 жыл бұрын
I never saw people used at 90 degree, usually people used it on straight line
@Crackshot2124 жыл бұрын
@@anon_acc it's called a cv joint, constant velocity joint if you're interested
@imyasuka3 жыл бұрын
it is ok, nothing special
@wojtekdobrowolski80844 жыл бұрын
No way! I just watched the first part and boom - you uploaded the second one!
@lin3ar_ch4 жыл бұрын
True lol
@lin3ar_ch4 жыл бұрын
Finish from part 1 and part 2 appear
@Pak_PakoBbl44 жыл бұрын
Same feelings
@SkinnySteve4 жыл бұрын
Same
@sohaibaljarih40084 жыл бұрын
Same lol
@pwaldechfal2 жыл бұрын
I like this way to discover these principles, and try to figure out a way to apply them on machines, and possible uses for everyday
@Wildkakahuette2 жыл бұрын
welcome to engineering :D
@AndreasIndustriePro4 жыл бұрын
me at 2 am: "I should go to bed now" youtube: *COGS*
@ethor48584 жыл бұрын
you think about cocks?
@mark787374 жыл бұрын
@@ethor4858 lmao
@herbertgunther89514 жыл бұрын
gues it should be CSGO
@dont_i_know48584 жыл бұрын
Coggers
@Dr.Al-Haitham4 жыл бұрын
@@ethor4858 🤛🦷🤜
@Patiboke4 жыл бұрын
3D print that stuff and you got yourself a kickass kinetic art exhibition!
@microArc4 жыл бұрын
fun fact: they use the design at 1:20 in the full-automatic NERF blasters to push darts into a set of flywheels. (the rapidstrike specifically, if you are curious)
@fa1nt3293 жыл бұрын
I really like this "Mechanical principles part 02" song
@_justice5703 жыл бұрын
mechankical prinps 🤠
@theseusization3 жыл бұрын
definitely wouldn't mind gaming to this song
@chriro09603 жыл бұрын
kzbin.info/www/bejne/h6rYYmV7Zrukp6M
@РоманСимонов-з2у4 жыл бұрын
0:24 looks amazing. Perfect rotation to linear movement transform.
@CamaradaArdi4 жыл бұрын
It's not that, the linear movement velocity is that of the sine of the gear
@astermelody4 жыл бұрын
@@CamaradaArdi The concept is that you can do both interchangeably, this goes for all of the examples.
@WiggyWamWam3 жыл бұрын
@@CamaradaArdi Yes but in what way is that not perfect
@Bananappleboy2 жыл бұрын
I like your words, funny mathematic man.
@kalekarri27964 жыл бұрын
cant even imagine which are the most insane combinations that exists.. just imagining some old huge machine somewhere in the world with insane amount of these.
@ilex_occulta2 жыл бұрын
you might like the song "the machine" by lemon demon
@kalekarri27962 жыл бұрын
@@ilex_occulta thats a nice song! :) just listened it
@liamhard62994 жыл бұрын
As an engineer, this is just mezmerizing to look at. You see the beauty and possibilities
@tiggyvolts90762 жыл бұрын
As a non-engineer I agree
@黄泉武蔵4 жыл бұрын
マジでこういうの考える人すごい。歯車の噛み合う角度維持しながら楕円設計するとか無理だよ。尊敬
@tizii0473 жыл бұрын
The KZbin recommendation algorythm remains a mystery
@Chloe115012 жыл бұрын
this is like an ASMR for the eyes
@PragmaticPhysicist24 жыл бұрын
Has anyone else been getting these mechanical concept videos in their recommended for no reason?
@phillhuddleston94454 жыл бұрын
yep, but it's still better than most everything else on KZbin.
@noregrets52584 жыл бұрын
Yup, came outa no where, but I'm still fascinated either way
@shrekwizowskee29104 жыл бұрын
anonymous person im not complaining
@slice62984 жыл бұрын
There is a reason An impossible thripple gear numberphile video i watched half year ago
@justsomeguy56284 жыл бұрын
KZbin knows what we want before we do.
@СергейБелый-н2ш4 жыл бұрын
Красава! Дуже доступно та взірцево! Вподобайка, звичайно ж!
@artofrendering4 жыл бұрын
Дякую, друже !
@furiousmat4 жыл бұрын
Thank you now I finally understand what I spent all this time learning when I did my degree in mechanical engineering.
@flameblade32 жыл бұрын
My favorites are definitely the ones that change the direction of the movement or change linear movement to rotational movement or vice versa
@matthiasbaron2452 жыл бұрын
Wow! The second animation is called 'Hypozykloidengradführung' in german. Few steam and combustion engines used this type of crankshaft mechanism. The advantage is no side friction on piston.
@xx_worldjaxx_xx14942 жыл бұрын
Man why does germany have the longest names for stuff
@beeble20032 жыл бұрын
@@xx_worldjaxx_xx1494 Because German loves to run several words into onereallylongword.
@okami-shaman95482 жыл бұрын
I've heard a German jokingly reffer to them as Frakenstien words
@babyaddyan67832 жыл бұрын
Ah yes the great
@sickmit34812 жыл бұрын
you mean Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz?
@rusdangel8583 жыл бұрын
Механика - прекрасное сочетание алгебры, геометрии и физики дополненное завораживающем движением. Этот притягивающий внимание процесс сродни волшебству! Она идеальна!
@chickendrawsdogs33432 жыл бұрын
1:55 - I remember that particular mechanism well, because it's what helps spreads the wings in the LEGO X-Wing.
@SkynetGenesis2 жыл бұрын
It's the basic gear and worm gear mechanism where only the worm gear can transmit the motion
@SoPLyA13 жыл бұрын
I don't know why I opened this video, but I was definitely satisfied
@abdullahtalha80024 жыл бұрын
Wouldn't it be 10 billion times better if you added the uses of these machines in the video!!! ANYWAY, I enjoyed it so much.....thanks for the video...
@moosemax63464 жыл бұрын
you can guess most of them even if you are not in the know, most of the where for circular motion to linear motion or some sort of energy transferrance between axis like at 1:49 and 0:43 is a old camera shutter thing or a version of it
@herbertgunther89514 жыл бұрын
disagree
@kelly8063 жыл бұрын
Great. Now I'm addicted to watching gear videos.
@demarcuscousinsthe65th Жыл бұрын
0:22 this is exactly how a crank shaft works, the rod going up and down acts as the piston, and the crankshaft is there to turn linear motion into rotational motion which powers the car.
@amalawawaw24 жыл бұрын
More of these please!!
@engineering_design4 жыл бұрын
I also have the best tutorials on my KZbin channel called Mt Engineering which is on CATIA V5 and solid works, which helps you to make this kind of animations, and many other things.
@xbloxmenx24733 жыл бұрын
This is so cool, senku gonna love this 10 billion percent
@peertube-ecosia4 жыл бұрын
This 2 videos taught me more about engineering than my university in 1 year. Keep going
@Someone259482 жыл бұрын
Constructing the constraint relations for these must be so fun! Going to sit down and do this one day for enjoyment
@holgerkrog85494 жыл бұрын
Damn, lego gets more complicated every day. Amazing!
@Tiquono2 жыл бұрын
Unironically cool video
@tntkit4 жыл бұрын
swiggly swoogly, your machine is working properly
@bfdzvalable4 жыл бұрын
The brilliance is in the simplicity. This is why we are at the top of the food chain.
@B4rb0ssa4 жыл бұрын
1:47 Those are 45 degree bevel gears, 1:55 That's a worm shaft and worm gear and 2:39 That's a rack and pinion setup with two racks
@UenzUenzenstein4 жыл бұрын
I never felt more enlightened
@yourlocalguardsman4 жыл бұрын
the lego technic department: *staring intensifies*
@anon49254 жыл бұрын
This is cool, I can imagine walking into some scary factory and see tese cool mechanical stuff. The music is great too.
@Lehrbua13 жыл бұрын
Mumbo jumbo: here is some simple redstone. The redstone:
@nicolasmeister21703 жыл бұрын
I've never seen a gear in my life but this fascinates me
@maks_i_mondo76394 жыл бұрын
it's very nice to watch, but could you add examples in which constructions these Mechanical principles are used?
@cat09no4 жыл бұрын
would be great
@acehandler15304 жыл бұрын
And titles for what the mechanical configuration is called?
@mobbdeep6154 жыл бұрын
i dont know much about mechanics but i doubt that most of these are used. they just look cool. theyre all probably way more compacted and improved to the point where them look similar because most of them serve the same purpose
@johnchristian77884 жыл бұрын
They are used to make KZbin videos!
@acehandler15304 жыл бұрын
@@johnchristian7788 Hmmm, well I'm not sure but ... I don't think so.
@willandersen36954 жыл бұрын
Idk why this has 1.9M views, but I was sure mesmerized the entire time
@miyabi_puri4 жыл бұрын
ほんと、開発者頭良すぎっしょ
@usurpvision Жыл бұрын
This video has elevated my consciousness.
@azimuth3614 жыл бұрын
This is one of those "Oddly satisfying" videos.
@TheRealFernancoTachanka2 жыл бұрын
Yes .. Unlimited knowledge!!!!
@TheFreakyFish2513 жыл бұрын
1:46 Hey! It’s those tan gear lego pieces xD
@bellerophonchallen88614 жыл бұрын
The stuff of everyday life, along with ball bearings and refined mineral oils. What makes your car go, and stop! what drives the shipping that moves your goods, what drives lathes and presses to make pots and pans, print books, wrap food etc. I can even see the mechanism for my concrete breaker that's taken away the need for a hammer and chisel and made my life easier.... Nice one.
@BlackStar-og6ef2 жыл бұрын
The renders are amazing. It will be great for viewers if you can mention the uses of these arrangements while they appear and their names.
@quatrebillesblanches64423 жыл бұрын
At twenty-three seconds, you delivered the solution for my moving piston. gratfull thanks
@ugi0623 жыл бұрын
0:56 This blew up my mind!
@guidomista70113 жыл бұрын
GOLDEN ROTATION OMG
@MrMindBlow3 жыл бұрын
Very interesting video! 👀
@ouiouispaghetti99954 жыл бұрын
Am I the only one who thinks this is really satisfying to watch
@reihan10304 жыл бұрын
Me : about to sleep KZbin algorithm : here's some cool video
@engineering_design4 жыл бұрын
I also have the best tutorials on my KZbin channel called Mt Engineering which is on CATIA V5 and solid works, which helps you to make this kind of animations, and many other things.
@suparnobolang36852 жыл бұрын
Sangat mengispirasi video ini.... 👍👍👍
@brickjam693 жыл бұрын
i have the one at 1:00 3D printed. it’s called nautilus gears and they’re super fun to play with
@Eddiee7573 жыл бұрын
Same
@earthlightsmusic2743 Жыл бұрын
Useful for getting increasing or decreasing gear ratio, such as for audio taper volume control.
@Xander_Reo3 жыл бұрын
Really satisfying to watch
@jhvudnsbcfhkdbnvb18684 жыл бұрын
This brings memories about calculations, durability of gear transmissions from my studies. Scarry...
@PhantomV23 Жыл бұрын
Lets be honest, Nobody looked this up. But we found it. And we liked it.
@lenudan4 жыл бұрын
Would love to see a practical application of the assembly at 2:14
@stefanritscher78684 жыл бұрын
Remote door locking mechanism
@MrRander77694 жыл бұрын
Looks to me like it would just spin about 3/4 of the way through a cycle
@immortaltitan38394 жыл бұрын
dear god yes
@ReLoadedProject4 жыл бұрын
look up faroarm its a measuring device, its not a perfect representation but if you see how it moves you will get what i mean.
@austinmorrison69533 жыл бұрын
Why is it so satisfying to watch these in action?
@GreatGloves4 жыл бұрын
Greetings from Finland!
@Gallus-gallus4 жыл бұрын
Perkele!
@djremotion24 жыл бұрын
hojohojo
@derkatwork334 жыл бұрын
Watches mechanisms move is truly its own reward.
@КопательМогил4 жыл бұрын
1:00 It's really genius
@arseniix4 жыл бұрын
No, that right gear hit in the transition between the fastest and slowest modes is gonna actually break the mechanism really soon
@derwolf2004 жыл бұрын
Yes it is, but it is also kinda useless. Where can you use the principle that the right wheel spins slow, then fast, then slow? Imagine that in a car gearbox where you have constant engine rpm but the car suddenly accelerates to 80 and then brakes back to 35 and then accelerates to 80 again without you touching any pedals. LOL
@icosahedron88824 жыл бұрын
Согласен
@-Burb4 жыл бұрын
@@derwolf200 That’s why cars don’t use them lol
@CamaradaArdi4 жыл бұрын
What are some applications to that? And how would you come about to fix the problem of the harsh hit of the cogs?
@arjumandvillagelife Жыл бұрын
great & interesting👍😊 respect from Gilgit-Baltistan👍❤
@Keln024 жыл бұрын
I should have studied that in uni :O It's one hell of a satisfaction
@rameshpandey91363 жыл бұрын
Amazing.😊😊 Stress Relieving
@MonahCinema4 жыл бұрын
Идеально для медитации и поиска Цы
@serega255654 жыл бұрын
Ходил на Мулан? Признавайся
@MonahCinema4 жыл бұрын
@@serega25565 нет. А ты подписался на мой канал? Колись.
@serega255654 жыл бұрын
@@MonahCinema Подписался, я тоже люблю машины
@MonahCinema4 жыл бұрын
@@serega25565 Красавчик! Но не только машины у меня.
@myequalmind3 жыл бұрын
this changed my life 🙏
@MysticalShadowDragon3 жыл бұрын
many of those look quite impractical for severy reasons from a mechanics point of view. like the one at 2:14 while that may work but theres too much tension in the entire system wich propaply will lead it to early failure if not maintained or oiled well enough. propaply will fail at higher speeds cause the entire part is too complex to operate BUT it has a high astetical value wich is somethin xD
@liggerstuxin12 жыл бұрын
This simple stuff amazes me cause someone has to visualize it first
@lukak17744 жыл бұрын
0:33 Isn't there a much more efficient way to get rotary to reciprocating?
@AToasterOven4 жыл бұрын
It's 3:30 in the morning and this is the most entertaining shit I've seen in a while
@thetitan69794 жыл бұрын
hey man i think all of these mechanism have a name right? could you add the names of them in the future. Most of them i already know but some are new to me and i would like to see what i could make with them. 3D print them and make some cool sculptures ad what not.
@Duke_of_Lorraine4 жыл бұрын
the double gear at 1:39 is an innovation by the french auto manufacturer Citroën to remove sideway torque. They made it their brand logo
@iloooveBOMBS4 жыл бұрын
@@Duke_of_Lorraine humm... i don't think they did lol, i see citroën's everyday and i never saw that as their logo.
@Duke_of_Lorraine4 жыл бұрын
the logo isn't the full wheel, but the chevron-shaped gear. cdn.1min30.com/wp-content/uploads/2017/08/Logo-Citro%C3%ABn-1.jpg
@iloooveBOMBS4 жыл бұрын
@@Duke_of_Lorraine Umm oh ok I understand know.
@ridhwan38963 жыл бұрын
Fascinating gears, indeed
@vineethpandalai74134 жыл бұрын
Hey great simulations, A request I have is, could you please include one or two examples of where these mechanisms are used in real life applications ? Because these are great and these are the ones we don't see/think often but are vital components of very important machinery we use on a daily basis. Also, could you please let me know which software you use to do these simulations ?
@microArc4 жыл бұрын
make it a passive side quest for yourself to find these mechanisms in things you interact with on a day-to-day basis. i think it makes life more interesting.
@sokuna24044 жыл бұрын
Several of those are used in your car. Automatic transmission use a planetary gearset, you will also find helical cut gears in your transmission. You will find a straight cut gear and gear racks in your power windows and power antenna. There are universal joints in the driveshaft. The differential will have beveled gears. The camshafts in the engine might be gear driven, chain driven or belt driven along with the accessory belts. Which also have tensioners and idlers. When you break down all the components required to make a car work you can look at how all of them transfer from the rotation of the crankshaft or electric motors powered by the battery which is recharged by the alternator which is powered by the accessory belt connected to the crank pulley connected to the crankshaft.
@liibaanibrahim25074 жыл бұрын
I never get tired of watching mechanic 💯💯💯👌👌
@UntakenNick3 жыл бұрын
2:13 I don't see why the middle shaft wouldn't stay in a vertical position indefinitely without any movement being further transmitted.
@slayer8actual3 жыл бұрын
Exactly! Why wouldn't it spin 360 degrees indefinitely? What makes it lay down 90 degrees to turn the connecting swivel? Nothing that I can see. Looks cool though....
@williamfoy5993 жыл бұрын
Reminds me of opening credits for Bicentennial Man starring Robin Williams
@Fightre_Flighte4 жыл бұрын
Okay, so a lot of this I can see a real world application for... But the hell is the use for what's depicted at about 2:15 ?
@Fightre_Flighte4 жыл бұрын
@Bla bla Dudel In what? Imean, this seems to waste a lot of energy. I don't know why you'd want that to be the case.
@ВасяКараев-ы9л4 жыл бұрын
Воистину - все гениальное просто.👆🏼👍
@victav4 жыл бұрын
I was watching this and remembered how I used to make the gears grind when I was still learning to drive stick... and I cringed pretty hard lol
@BubbasToyReviews3 жыл бұрын
it's so satisfying watching the bumps go into the grooves
@tailoramit44 жыл бұрын
Woww, it's really nice but can you please mention name of working principal also
@Squash3r2 жыл бұрын
I have seen the best video of my life
@ugi0623 жыл бұрын
What schools needs to teach: What they teach: *pLanTs HaS chLoroPhyll*