circuit/block-diagram drawing

Question

I\'m looking for either algorithms or visualization tool for (nice) circuit/block-diagram drawing.

I am also interested in a general formulation of the problem.

Answer 1

Here is one: http://www.physicsbox.com/indexsolveelec2en.html

Here is where to look for others:

http://www.freebyte.com/electronics/

www.educypedia.be/electronics/easoftsim.htm