.....in Prague,as an art sculpture,you can enjoy simply with a click on :
http://www.travelpod.com/travel-phot o/gtrob/europe_2006/1148282160/dscf0231.jpg/tpod.html
It can make us think among so many applications...about the shadouf,or about Milkovic"s "hammer with a pendulum" (this time with a telescopic counterweight...).
This telescopic (if variable...) "addition" ...can be on the same line with the "long arm-short arm ",recurring theme associated with our topic...
All the best! / Alex