Recursive racks

[@liambohl]

These demos remind me of the Hoberman Sphere - that spiky ball toy that expands and contracts through a bunch of linked scissor mechanisms. The Hoberman Sphere is recursive too, except there the components have a network of relationships rather than just a chain of relationships.

[@kipper1668]

We used to have one of those! It was super fun to play with and toss around :)

[@KarolOfGutovo]

Commonly seen on indulgence feasts in Poland - stands with cheap (often knockoff) toys, sweets and especially indulgence obwarzanki (a very light and dry kind of ring shaped bread, no idea how it's made, availble basically only on those indulgence feasts) spring up around churches on the day of that church's patron. Usually in summer. I remember having that kind of toy, but idk if it's still somewhere around in the house.

[@chargehanger]

isn't it offically called the "Ikea Death Star" now ?

[@Fillex5000]

technically you could say that it's an inverted hoberman sphere. Inversion is a geometrical transformation which (in 3d) changes planes into spheres and vice versa.

[@nikthefix8918]

I tried to put a servo on one of the joints of a plastic Hoberman Sphere so that I could remotely expand and contract it for dramatic effect. It didn't really work as my servo didn't have enough torque. I wondered if the sphere I had relied to some extent on the flexibility of the thin plastic struts or whether a solid metal construction would also work if the joints were ball / socket.

[@mysticmarble94]

I'm just shocked how damn smooth that contraption works 😲😲😲

[@henryseg]

It helps that there's a bit of vaseline on the racks...

[@bennytyty]

How did I look at this thumbnail + title and instantly think "that's a Henry Segerman video" 😂 Mans got a style

[@dhayes5143]

That's so funny, for me I thought it was just an engineering student/someone with a 3d printer, this seemed far too non-abstract to be a Segerman video lol. But obviously you understand something I don't😅.

[@rmt3589]

*does the default dance from Henry Stickman*

[@Zakru]

Saw the title and thumbnail, thought "cool", clicked and thought "seems a bit like what Henry Segerman would do-"

[@5tarSailor]

Your pfp takes me back

[@HeroReborn]

Your PFP tells me you're Loyal to the Herd.

[@RandomAmbles]

I really want to see a machinist like This Old Tony make some of these and see if he can come up with a practical function for them, like perhaps for shelving or something. Utterly fascinating and deeply original, as always it seems. You never cease to astound me!

[@lewsdiod]

You really do explore some wondrous mechanisms that are very mesmerizing to watch in motion! Thanks for all your brain scratching displays!

[@user-pw5do6tu7i]

i love the no bs intro. 7s of displaying something really cool then on to explaining it.

[@mint530]

I quite like the unique way this mechanism behaves! I think the most interesting thing about these recursive mechanisms is how it made me really look at the different reference points when figuring out how it behaved :)

[@donaldhosford5194]

Love the video! If you take the first design, add a pin to the center box (attaching it to the surface below it), add another pin to the end of the left most gear rack, and a marker to the end of the right most gear rack. You will get a drawing copy machine! Love it!

[@pseudo_goose]

I always love the mechanisms that you come up with. It just got way better, now that I realized I also have a 3D printer!

[@henryseg]

Please add a make to the printables page if you make some of these!

[@pseudo_goose]

@@henryseg Will do! Working on my second color right now

[@holyorderofscientists]

As a scientist who has solved most of the problems of the world I still have to watch this video over and over again to get how it really is working. It helps to have the as real objects in the hand so one can observe the behavior. You Henry are one big genious is all I can say. Thanks 1000 times for posting this piece of art and technology.

[@benjaminparker5044]

Seeing how the original worked, and then seeing the second one, I was actually pretty happy with myself for being able to work out how the second one would work relatively quickly. That being said, once you did confirm it, I immediately thought of trying to find a way to use these and other slightly modified racks to act as logic gates. Would be very interesting.

[@meem093]

Having Caleb Widogast explain an expanding mechanism was something I didn't know I needed.

[@MrBotdotnet]

this feels like such a cool thing to be able to pull out at a party these mechanisms are just so cool and satisfying!

[@CoughSyrup]

Oh man, that movement is buttery smooth

[@YigalBZ]

One of the best ideas I ever seen! So smart, so simple, so mechanic! Well done.

[@adhidwipa6027]

Satisfying yet functioning and incredibly fast-responsive mechanism. Nice extra details from prior projects you had included in this video.

[@neepsmcfly4176]

I dig the inadvertent optical illusion! As the boxes are drawn together, they appear to grow bigger.

[@comeradecoyote]

This reminds me of pantogarph mechanisms like used in various extension mechanism. Your last example in particular looks like a different take on a mechanism oft used in drafting machine, whereas the top bracket and the end unit must always stay parrallel relative to one another (so that lines remain parrallel). In these machines this was at first accomplished with a pantograph, with two rods comprising each segment of the arm. On later american machines, they switch to steel belts, which are put in tension so that they grip their respective wheels. The top and bottom disks are fixed, as is the elbow of the machine; so whatever movement is affected, the end still stays parallel. In very nice machines, the steel belt was welded in a manner as to never loose tension. Cheaper models used a belt with a tensioning nut on each band and their loosening could cause errors in the drawing. However the geared rack idea perhaps could be applied in keeping those two points fixed in a different manner. Either with solid racks around toothed gears, or perhaps with a toothed belt.

[@pepe6666]

very thought provoking. i feel like these demonstrate the concept of multiplication via repeated addition

[@pedrohenriqueboscofi]

Incredible the last rotating example!

[@Wintergatan_2]

Spooky action at a distance indeed 🔥

[@CoughSyrup]

Henry Segerman videos never disappoint

[@pepiggy114]

That's a delightful movement.

[@escplan1011]

This reminds me of what would happen if you moved one part of a portal into the other end. Looks awesome!

[@aeremthirteen2771]

I swear, this will be how certain meta-materials will work some day when we can get consistent "gears" made of bio-mechanical components/layers. I imagine this could be a great mechanism for frequency combing.

[@incription]

Such has been created already, the issue is mass producing them

[@aeremthirteen2771]

@incription Id love to see articles/li ks if you have any, friend! Gears even? :o

[@incription]

@@aeremthirteen2771 Paper is called "Step-by-step rotation of a molecule-gear mounted on an atomic-scale axis". Also "A Simple Example of a Molecule-Gear Train: PF3 Molecules on a Cu(111) Surface"

[@NigelTolley]

Not seen it done with cogs, but there's materials now that get fatter when stretched, for example.

[@aeremthirteen2771]

Im very excited for the self-evident impending analog computer renaissance! Minimizing AI control system energy requirements is all we need now, and quantum paradigms are expanding into a new knowledge tree/growth more and more exponentially lately!

[@__8120]

How you managed to get the action so incredibly smooth on 3D printed parts is simply beyond me

[@HaloWolf102]

\ Vaseline /

[@zhinkunakur4751]

@@HaloWolf102 lubricant UwU

[@alexnepu1561]

I feel like the last contraption makes an involute curve It interesting to see what kind of movement you get with only racks and gear and the application they can have

[@seedmole]

Good example of the breadth of results possible when considering inverting a member of a recursive structure.

[@jubb1984]

I love the future, thanks to 3d printing, streaming services, i can watch this wonderful lesson in recursive mechanics ^^ Thanks for this!

[@willemvandebeek]

Fascinating, I can see this being great for extending solar panels on a spacecraft.

[@punkdigerati]

This reminds me of K'NEX and ERECTOR sets. Many fun times as a kid.

[@EastonBullDog]

Just wonderful - this is as beautiful as it is functional. Thank you for sharing!

[@lumotroph]

This makes me so intrigued about this idea I had years ago to make a mechanical software interface. This would be the perfect set of mechanisms to make photoshops basic transformation tools!

[@samuelmiller2552]

Yessss, 10 seconds in and I was hoping he would do it, and he did at the very end.

[@byeluvby]

That motion is mesmerizing

[@Engineezy]

This is amazing! Going to have to incorporate it into my Rube Goldberg project!

[@batlin]

10:26 this one reminds me of watching the overcomplicated windscreen wiper mechanisms on buses in late 1980s Ireland. Mesmerising and yet almost perpetually broken...

[@lexibyday9504]

these would be great fun incorporated into children's toys

[@45nickname]

You probably dont see this a a proble to solve but, You could force the first, and I thing second, recursive rack and pinion to be flat (not stair stepped) by fixing the height of each rack to a constant value based on orientation. It would require a means of selecting the height of the rack fixed to the box to 1 of 4 values, either with spacers or custom shapes for each orientation. But completely doable

[@klyesam4006]

This could make a cool puzzle game. Where you have a given input and output and you need to place the racks.

[@Rubrickety]

Shapeways is going to lose a lot of business now that Henry has developed the ability to magically bring parts into existence by simply pointing his finger. 😉

[@oncedidactic]

Played with the gear cube at opensauce and found it delightful. There’s always a small surprise when it arrives perfectly cube or perfectly flat from its intermediate folded states. The “recursiveness” of these makes me wonder about how you would formulate an energy transfer equation for n segments. That exploding outro was great 😆

[@corncake4677]

I love your contraptions

[@gjum42]

I'd love to see what can be done using different gear ratios between "incoming" and "outgoing" racks of each box. Would it just change the slope of the diagonal movements of adjacent boxes or can you create more complex movements using that?

[@Gulyus]

Sorry made a comment twice and deleted. Thinking about this is difficult at 4am. Especially when I misinterpret the device for 6 minutes because I was typing lol. Anyway, I think if you put gears pairs into the boxes with correct ratios it should be possible? It would basically twist the path a little if you did achieve it though, shouldn't allow any more complicated movements. Though I must confess I can't think of what other movements this system can really produce.

[@saityavuz76]

You make my world much more interesting, thank you!

[@Autoskip]

The pure rack and pinion recursive mechanisms could absolutely work without the constant step up every iteration - if you take either version rotated to a vertical grid, the similarly orientated racks obviously never cross over each other, the horizontal grey racks never cross over with the vertical green racks, and the vertical grey racks never cross over with the horizontal green racks, so there are two separate sets of racks that could each occupy one vertical space without ever colliding with each other. That said, you would need to tweak the design slightly - I doubt you could just rearrange the parts you've already made to do that.

[@bonkser]

w

[@blacklight683]

So simple yet so cool

[@karnpandharipande]

This reminds me of the Hoberman Sphere, very nice!

[@NathalieHaHa]

I think it could be a very interesting exercise to see if you could use specific combinations of these to create "linkages" that trace specific paths, similar to Fourier epicycles

[@matthewrberning]

Absolutely lovely, thank you for sharing!

[@The_Totes_Adorbs]

I'm big dumb... but this was so visually satisfying... asmr at it's finest.

[@ewerybody]

So satisfying to look at 😊

[@KylejvT]

As somebody who prints and unpowders alot of your models its always great when I see them come through! Would it be possible to make a cube with recursive racks? Some thing like a Hoberman sphere or similar.

[@simonlinser8286]

They used to have those really cool expanding globes that were made of plastic too

[@TheAbyssalStorm]

@@simonlinser8286 I think I still have one of those somewhere on my shelf. May have given it to my nephew though.

[@d3j4v00]

@@simonlinser8286that’s what a Hoberman Sphere is mate

[@gdutfulkbhh7537]

"Alot"?

[@peipol96]

if sufficiently small or large it can scale pixel art within the distance that the illusion takes place. Thanks for this kind of videos Henry greetings from Venezuela

[@pandaqwanda]

that's actually really cool, subscribed!

[@monopal2330]

What about curving the racks? I wonder what it would do.

[@freeshavaacadooo1095]

It's like a scissor lift but with gears. Neat.

[@novantha1]

That first gearset would make for a super interesting mechanism for a light sliding door.

[@zim_the_vixen]

Aaaa this is so cool! The only thing we feel is missing is experimenting with different gearing ratios.

[@MildMisanthropeMaybeMassive]

I can see these as children’s toys or scaled up for modular shelves/framing, and some mechanism for duplicate processes.

[@MrMacGaunaa]

It would be fun to see what kind of fun mechanisms you could come up with by making the straight racks curved. So in addition to translation you'd get also rotation.

[@muffty1337]

This is kinda magical.

[@robithrifky5442]

Amazing mechanism man...

[@DonCarlione973]

I really like these. Great job👍🏼

[@undersky596]

God I love your videos. Thank you for bringing me ideas to me for drawing

[@robertbcardoza]

This has ‘clockwork theory of everything’ energy

[@blockfifteen]

you always amaze me henry! I have yet to watch the video, but props for what you do in the field of mathematics and 3d design!

[@fhdang8978]

This is so interesting I’m definitely subscribing if there’s more stuff like this

[@CreepyChappy]

Beautiful work

[@IlSharmouta]

you could absolutely sell these as fidget mechanisms. I'd love to have one on my desk.

[@henryseg]

If you have access to a 3d printer you can make your own! Link in the description.

[@clangauss4155]

Haven't thought about boxes and racks this hard since high school

[@ModelLights]

Ha that's hilarious. At 5:29 when you were talking about you could remove the gear as long as the box held the 2 pieces and they slid together, the first thing that popped into mind was driving them like the slotted straight driven lock/key combination shown 2 or 3 years ago in one of the lock picking videos. Then at 5:36 of course you pull out exactly that, a straight drive push gear mechanism. There's a lock based on changing the teeth of that mechanism so the matching key opens it. Fairly simple and not very secure, pretty sure they said just shoving a vegetable into it would usually open the locks. Used in Russia or Scandinavia etc for simple things like shed doors, the video showed one outside somewhere.

[@BritishBeachcomber]

3D printing uas totally transformed the way we turn imagination into machines. Now we just need to find a practical use for them.

[@AnInnocuousBlueCube]

Future Ratchet & Clank Unnecessarily Complicated Bridge Mechanism Builder in the making.

[@LukaszWiklendt]

These remind me of the infinite continuity splines mentioned in Freya Holmér's video "The Continuity of Splines".

[@rianfelis3156]

That first one definitely reminds me of a pantograph in operation

[@ModelLights]

Of course it's very similar to the multiple scissors type reach grabber. Operate one scissors, the closing of one closes the handle of the next, etc etc. 'Scissors grabber' will turn up may of the long reach type on google..

[@henryseg]

Yes, I have also made designs based on scissor linkages. And depending on how strict you want the analogy to be, I think you could also call them recursive mechanisms.

[@miximum1]

I love how racks move

[@avaraportti1873]

Telling the wife I'm watching a video about racks

[@TheRealStructurer]

Very nice even if I can’t think of an application where it can be used 😉 Thanks for sharing 👍🏼

[@hamish_todd]

We know he's heading towards some kind of analogue computer made with these things...

[@Jandodev]

These are really cool!

[@bennyellis3512]

Oh dude😮 DUDE😳 Wow, just wow🤓 Bravo👍 Oh and once you explain its meaning Iove the name

[@maddoxmonteza]

Wow so cool.

[@domsau2]

Nice technical art.

[@theawesomer]

Fascinating. I wonder how large of a recursive rack and pinion model you could build before it was too hard to move by hand.

[@postscript1561]

I would love to see some practical applications to these mechanisms. The parallels of the racks and of arbitrary points of the racks look like there should be ways to take advantage of it, but it is hard to envision with the video only demonstrating the simplest form of the mechanism.

[@RoboFuntastic]

OH MY GOD That is so and smooth as F I gonna install the motor in it to keep reapting the motion for my youtube background

[@Kids_Scissors]

What I also find interesting is that the first chain keeps a constant width no matter what its position is

[@iDor2]

recursive racks? I call that passive income💯💯

[@Quickmask561]

Talk about a hook! That first looked made me drop my jaw, no joke.

[@perfredlund]

Nice! If the green boxes start in a line, they will stay on he same line. Same with the grey boxes. Cool concept :D

[@unkown1600]

Mechanism is quite cool

[@mutanthenmars8323]

this made me smile =]

[@renny_alt]

this works almost exactly the same way as a cascading linear lift, except with rack and pinion gearing instead of chains and sprockets!

[@dfto13]

Весёлые взаимодействия между деталями. Механика выглядит круто.

[@j1t176]

you should make a book or document of all the mechanisms you've designed

[@henryseg]

I’m working on the second edition of my book, with a new chapter on mechanisms. So, it’s on the way!

[@wolviex]

I'd love to see these with the boxes at some angle other than 90 degrees. You'd end up with some kind of rotational symmetry as well!

[@nkumar1]

Using just 4 of these will make a nice clamp for soldering PCBs

[@billyeag99]

This would be a great tool for building stairs