Today’s invention is a collection of nested enclosures, which slide into and out of one another like drawers in a cabinet. A telescoping action is envisaged which would allow the formation of zigzag or spiral machines which could be squeezed into the volume of the original drawer.
The sliders could be made robust and lockable, in order to make the extended structure rigid or motorised so as to allow the whole system to propel itself across terrain or through water.
The drawers need not be rectilinear of course, resulting in interesting geometrically irregular, compressible machines.
As to applications…well I guess robot limbs or staircases or movable bridges are all possibles.