Does there exist such a beast?
More information re use is needed in order to well answer
this. There are various things that can give the illusion,
at least, to doing this. (That almost suggests
decorativetying, doesn't it?!
)
The
versatackle mechanism might come closest to doing
the trick, as when hauling those structures tight, the parts
that will end up doing the binding (and which are wrongly
counted in figuring rough mechanical advantage) can go
pretty slack, out of the way; whereas most other possible
solutions are what I call "Paul Bunyan" structures --they
demand greater force in setting than they deliver (the force
needed to overcome the very friction that will secure them).
E.g., one could form a
Prusik structure in the SPart and
run the tail back through this; setting tight would come by
pressing one hand against this knot and hauling the tail
through it, the increasing force ever building resistance
to the tightening. There are simpler such contraptions;
there might be some that "remain tight" in a sufficiently
long enough temporary state to allow one to tie off the
knot securely, which might meet some need (in contrast
to simply letting go and being done). Now, that was for
the "remaining tight" part; anyone want it later to be
untied? Hmmmm, ... !
So, your friends' exact needs ...
.
.
.
might just be to see if you can do any useful knotting.
(Or if whom you associate with are worth much!)
postscript : I should remark about the Subject wording
--re "zip tie". I take this to be those ratcheting plastic
securing bands. In good ol' American buy-&-trash behavior,
these petroleum products are wasted more than they need
be : they usually can be undone, by inserting something
(sufficiently thin, narrow, & strong) to push the locking
tongue back so that the band can be slid undone.
Recently I found some in use at an arts festival for holding
signs that were large enough that one could effect the
release with a thumbnail! Great!
