Is there any software, preferably free, preferably supporting drag & drop, preferably supporting save & load to ease the creation diagrams like these?

Is there any software, preferably free, preferably supporting drag & drop, preferably supporting save & load to ease the creation diagrams like these?

_{(source: tikilive.org)}

Is there any software (preferably free, preferably supporting drag & drop, preferably supporting save & load) to ease the creation images like these?

And is there a name for these types of images? (I just guessed it could be called "relational illustrations", hence the title)

Is there any software, preferably free, preferably supporting drag & drop, preferably supporting save & load to ease the creation diagrams like these?

(if this is the wrong place to ask, sorry. any idea where i could ask?)
is there any software (preferably free, preferably supporting drag & drop, preferably supporting save & load) to ease the creation images like these? and is there a name for these types of images? (i just guessed it could be called "relational illustrations", hence the title)

http://v4manual.tikilive.org/wp-content/uploads/2011/07/connecting-video-source-1.png

Is there any software (preferably free, preferably supporting drag & drop, preferably supporting save & load) to ease the creation images like these?

And is there a name for these types of images? (I just guessed it could be called "relational illustrations", hence the title)