h a l f b a k e r yPoof of concept
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Now balloons work by buoyancy & displacement, & there's nothing lighter than a vacuum.
A vacuum balloon (for those that don't know) is a rigid balloon from which (rather than pushing it out with another lighter gas like helium) the air has been pumped out.
The idea of course has been done to death
(I think it was an (Italian?) monk over 100 years ago who first hit on the idea) & it's just not doable, at normal sea level atmospheric pressures that is.
The simple problem is that air pressure crushes your rigid balloon (reducing the space inside, which naturally reduces the area of vacuum, so reducing its lifting properties) & any material or internal bracing (currently available) strong enough to withstand the pressure will completely negate any buoyancy achieved with it's weight.
However...
If you build your vacuum balloon in space there's no air pressure to crush it.
Then as its orbit deteriorates & it re-enters the atmosphere displacement will keep it aloft.
The air pressure at such rarefied heights being much less than down here only a moderately strong rigid material should suffice to compensate for it's external pressure & so the balloon remains aloft indefinitely.
So what's the point?
Well, satellites equipped with one of what we at SkewInc. like to call our thin-steel-skinned-vacuum-zeppelin (our R&D guys aren't very good at names) need never again be a hazard to sheep in rural Australia or Russian cities as it falls flaming from the sky, because it never will, it just hangs there.
Enough of these would also make a pretty good solar shield thus solving our global warming problems, a secondary project our R&D department is currently working on.
The only drawback is that it's going to get a bit cluttered up there, we may have to forget about any future space launches.
spinny vacuum blimp
_22Prayer_20Wheel_22_20Vacuum_20Blimp
[FlyingToaster, Jul 06 2014]
Least on-topic link on this page.
http://www.google.com/patents/US1829474
Flying in circles. [MaxwellBuchanan, Jul 06 2014]
slightly more relevant link
https://www.youtube...5_VvTxZM&feature=kp
[2 fries shy of a happy meal, Jul 07 2014]
Aerogel Vacuum Balloons
Aerogel_20Vacuum_20Balloons
Posted in 2008 [Vernon, Jul 07 2014]
Buoyancy/thrust hybrid high altitude baloon
Buoyancy_2fthrust_2...20altitude_20baloon
[Skewed, Jul 07 2014]
Space hoppers
http://www.lolc.co....:Space_Hopper_1.jpg
[not_morrison_rm, Jul 08 2014]
Boing 737 fuselages go white water rafting
https://s.yimg.com/...ailment-19rha02.jpg
[not_morrison_rm, Jul 09 2014]
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<Sits back & waits for cries of 'poppycock'> ;) |
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Well, damn. I just wrote a full page of maths to
annotate this idea, and while I was doing it the
idea changed spelling and all was lost. |
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So, you'll just have to take my word for it that: |
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(a) A vacuum balloon which is infeasible at ground
level is equally infeasible at any atmospheric
pressure. |
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(b) Vacuum balloons become perfectly feasible (at
any atmospheric pressure) if they are large
enough. |
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(c) Light gases are a much more sensible thing to
fill a balloon with than vacuum. |
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//Well, damn. I just wrote a full page of maths to annotate this idea, and while I was doing it the idea changed spelling and all was lost// |
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'Boancy' by any chance ;) |
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(c) We here at SkewInc. think sensible is overrated & have never let it cloud our thinking, or at least we try not to, sometimes we need a little extra beer to keep it at bay, but then who doesn't. |
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(b) And we have so much space in um... space, we can make it as big as we want. |
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<was hoping to get more mileage from this before anyone noticed> |
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Howsoever, I refer you to (b) & (c), but most especially (b), where you (appear to) say it might work ;) |
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You could also cite a proof-of-concept experiment.
Space is full of vacuum, famously large, and floats
well above the Earth's atmosphere. |
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Yeah, but the most readily identifiable hogwash in my
thesis (which you readily identified far too soon) remains. |
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//air pressure at such rarefied heights being much less than
down here only a moderately strong rigid material should
suffice// |
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With less air density comes less lift / cubic meter so for
buoyancy the construct must weigh less, which means you
have to use lighter material for the rigid skin which tends to
mean it's crushable by the lighter air pressure. |
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Or as you more succinctly put it (a). |
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However new materials all the time, aerogel case in point. |
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This is so counterintuitive I don't really believe it (in that deep seated little bit of the brain we call the subconscious), that a vacuum filled copper sphere (if the copper were thin enough to weigh less than the volume of air normally encompassed while somehow miraculously remaining strong enough not to crumple like a Styrofoam cup lowered into a deep sea chasm) can somehow be lighter than air. |
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I keep thinking there must be something fundamentally wrong with it (like perpetual motion). |
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For my next suggestion I will be proposing anti-gravity through centrifugal force by swiftly waving a large weight back a forth (in a short arc) above your head. |
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//For my next suggestion I will be proposing anti-
gravity through centrifugal force by swiftly swinging a
large weight back a forth above your head.// |
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Of course, anti-gravity through "centrifugal force" is
basically what orbit is. Baked? |
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Actually, you can make a jolly good vacuum balloon
out of Kevlar if you spin it fast enough so that the
centripugal force on the walls counters the air
pressure. |
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^with the caveat that structure is still needed to mitigate axial compression <link>. |
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I knood I'd seen it. Kudosses to [FT]. |
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Ah but no [Matt], in this sense an orbit is essential omni-directional, at the end of the day (orbit) you still haven't gone anywhere. |
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For a centrifugal force to work as anti-gravity & provide a forward (or upward) motion it needs to have the net effect of a uni-directional force. |
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If you swing the weight through only 180 degrees over your head you get a net upward force but in stopping it to prevent it completing the circle (orbit) you transfer an equal force down. |
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To make it work you need a teleportation device that would transport the weight directly from one point of its arc on the down swing (thus avoiding the equal & opposite force bit) & rematerializes it on the upswing cutting out 180 degrees of the full orbit as it where. |
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It's probably going to be easier to take the stairs. |
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But can it blend ? I think (b) tends to mitigate (a) somewhat. Up in the sky where the pressure is nigh, the construction can be rather lightweight. |
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Out there in the net, somebody made the point that on Jupiter an aerostat would have to be vacuum (since the atmosphere is already Hydrogen). |
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On Jupiter I believe they use hot hydrogen. |
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Of course you have to be careful with the burner. |
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[Toaster] clearly wins the cookie, like [Max] said, Kudos. |
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Now I have to read yours [Toaster], oh, & [caspian]'s & [Max]'s, & the other links (which will all surely all lead to others). |
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Good grief, tis true there truly is nothing new & history is indeed circular, even down to jokes about anti-gravity / levitation |
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//For my next suggestion I will be proposing anti-gravity through centrifugal force// |
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//For my next trick, levitation using a simple set of bootlaces// |
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The ultimate implementation for your idea appears to be to take an empty paper bag into space and open it thus deploying its capacity as a vacuum envelope. Then. What. |
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//probably going to be easier to take the stairs// |
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(c) again, plus much less fun. |
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<edit> sp.: alert, thanks, fixed (the ones found). |
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//On Jupiter I believe they use hot hydrogen// //have to be careful with the burner// |
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I do believe I may have just wet myself laughing. |
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On the subject of swinging weights to effect
antigravity, there was (and indeed perhaps still is) a
system for airlifting people or objects, and also for
lowering them to the ground, which involved the
aircraft flying in circles as the cable was extended
(or retracted). |
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//b) tends to mitigate (a) somewhat// |
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//With less air density comes less weight / cubic meter so for buoyancy the construct must weigh less, which means you have to use lighter material for the rigid skin which tends to mean it's crushable by the lighter air pressure// |
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Your spinning version might help do the trick, not sure how that stops pressure crushing it flat along the other lines though (but I haven't had chance to read it yet)? |
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[WcW] did you read the bit after "So what's the point?" |
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Stop satellites crashing to earth when their orbit degrades / use in large numbers as a solar shield to avert global warming / or, use them as advertising blimps for adverts targeting a demographic which includes owning a strong enough telescope to read said adds. |
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huh? swinging them in a circle below the aircraft [Max], sounds dangerous, especially being lowered with high speed lateral movement (ok circular) toward uncertain terrain, have I understood that right? |
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The point was that the aeroplane flies in circles;
the person (or object) on the end of the line stays
still in the middle, apart from being lowered
slowly. |
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It's roughly equivalent to the aeroplane standing
still and the person, suspended on a long line,
swinging in circles under the plane. Except the
plane moves instead of the person. |
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The HB is one of the few places where someone
will tell me what this system was called and
provide a link. And it will probably be [8th]. |
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[EDIT] My esteemed colleague [MaxwellBuchanan]
found the patent <link> |
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Ah, I can see it now, & how it would be useful (just don't ask me to explain it cos I only see it the same way my hand knows how to catch a ball as it were). |
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I think we may have gone through this once before, with the compressed vacuum tank. |
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Obviously the balloon, when in contact with the upper layers of the atmosphere, could be made more rigid by releasing some of the compressed vacuum from the tank. |
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More like 3 or 4 at a guess, maybe more, I've not followed & read all the links yet so not sure. |
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Though in my defence I've not found anyone else suggesting space or high altitude construction or either of the uses I suggested, yet. |
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That said I think [FT]'s one (only one partially read so far) beats this hands down. |
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//made more rigid by releasing some of the compressed vacuum// |
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Not wishing to be overly pedantic (having more than enough errors of my own, this one wasn't meant to be serious after all), but might you want to reconsider the wording there? |
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<Later (post [not_morrison] anno below) edit> suspecting irony & that it may be a set up for some sort of punchline are also reasons not to be overly vehement about perceived errors. |
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Vacuum is the easiest thing to compress, the presence of even the slightest trace of gas or liquid makes it more difficult, heat buildups and stuff like that. |
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Can I like this idea even though I have no idea if it can work?
whup too late m'already doin it. |
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I feel a sudden urge to riff on an oft repeated refrain, if lonely inks could be bunned, that one would I bun ;) |
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<Now has images of steampunk vacuum craft blazing through the sky to merge suddenly with geography after sudden catastrophic decompression> |
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//Can I like this idea even though I have no idea if it can work?// |
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I doubt you can like it as much as I like that link [2 fries], or the idea of compressing & releasing a vacuum ;) |
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To shamelessly steal a line from [Vernon]'s Aerogel Vacuum Balloons (thanks for the link [Vern]). |
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//it may not even need to be fully evacuated// //a partial-pressure balloon wouldn't have to resist as much air pressure// |
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But then you no longer have a vacuum balloon? |
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Or is the recompression, as the air is going in, not
out.. |
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No air going in (until after the event), or it wouldn't crunch. |
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Still right about my misuse of the word though, already lacks 'compression' but couldn't think of another. |
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I'll vote for partial-pressure to be synonymous with vacuum in this instance. |
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For this idea, if your target was say 60k feet where there's only 1psi ambient, you could build it on the ground, depressurize it to 13psi (in ambient 14.1) then float it up, pumping air out as you go, until it's at 0psi inside, at 60k ft. |
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Thus rising to the very edge of space without all the messy rockets, from where with a little boost with an on-board chemical rocket it carried up it skips across the boundary & floats off into orbit, or escape velocity. |
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At last, a fuel-cheap re-usable ground-to-space vehicle! |
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SkewInc. in partnership with ToasterTech. proudly present their Space Blimp (patent pending)!! |
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Should we start another idea ;) |
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Accept there already is, this is what [ixnaum]'s Buoyancy/thrust hybrid high altitude balloon is all about (the idea that got me started on this one). |
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//a little boost with an on-board chemical rocket it
carried up it skips across the boundary & floats off
into orbit// |
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"skips" = "is accelerated to the tangential speed of
≥7km/s required for low earth orbit". You may also
want to reconsider "floats". |
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Nah, floats sounds far more... floaty. |
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It makes for a better advertising sound bite, ditto skips (accept the sounding floaty part). |
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Of course, we've now mutated into [ixnaum]'s [Buoyancy/thrust hybrid high altitude balloon] which wasn't what this was supposed to be about. |
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A reiteration of the actual idea is in order: |
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Construct in space & strap to satellites so when orbit decays they float around in the upper atmosphere instead of crashing to earth. |
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Like the sunk ships (Angamurak?) mentions in Pratchett's "Going Postal". |
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//they float around in the upper atmosphere instead of crashing to earth. |
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You mention the long piece of fishing line, so they can be gently pulled back down to the surface and recycled.. |
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Well, I was going to leave them there to act (in sufficient numbers) as a solar shield, was worried about the hazard to new space launches though. |
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What gauge fishing line where you proposing? |
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Thinking about it....maybe some prior art in the form of space hoppers...link. |
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Used to have one of those, I found it singularly useless for getting around on, gripped by the horns & swung overhead however it made an excellent bludgeon with which to club my little brother. |
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Just goes to show, you can find a use for anything, & it's not always the one the manufacturer imagined. |
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<edit> What happened to the Boeing 737 anno? |
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<further edit> Space hoppers? a little confused about the prior art here (ok, I have no idea, but I'm sure there's a joke in there somewhere & I'm dying to know what it is). |
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//On Jupiter I believe they use hot hydrogen// //Of course you have to be careful with the burner// |
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[Max], I've managed to make some enquiries & according to my contacts on Jupiter they don't use burners. |
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Apparently you simply grip the balloon between your knees & rub it with both hands until sufficient heat has been generated by the friction to warm the gas, to make the balloon rise further or faster you just rub more briskly (or at the same speed for longer), of course you have to be careful not to over do it in case the balloon swells too much & bursts. |
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Oh & you've been put on their no-fly list, I'm afraid that in posing my questions I may have inadvertently let slip your idea about using burners in their hydrogen heavy atmosphere, they got a bit upset about it. |
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Damn. Well, there goes my "Surf The Great Red
Spot" adventure holiday plan. |
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//"Surf The Great Red Spot" adventure holiday plan. |
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You need to get that up and running before some company uses it as a promo for an anti-acne treatment. |
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//<edit> What happened to the Boeing 737 anno? |
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I'd just marshalled half a dozen Google results & was sitting down to scan through them for an angle, when poof! ;p |
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Not that I'm complaining (can't, probably a worse offender). |
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<often edits on the page himself, for unnecessary repetition, blatantly stupid / offensive anno's (in his own paradigm) that sounded good as typed but on scanning appear otherwise & even (strangely) aesthetics> |
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Unfickled. See Boing linky. |
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