Somehow I had never heard of the Pentagram of Venus before reading about it in an excellent Azimuth post by John Baez:
[url]http://johncarlosbaez.wordpress.com/2014/01/04/the-pentagram-of-venus/[/url]
Of course I wanted to make it in GeoGebra, and of course I wanted to generalize it. The view checkboxes let you switch your reference frame, the settings let you quickly compare Venus-Earth and Earth-Mars, or switch to aany possibility in the Settings. Necessary planetary info can be found at:
[url]http://www.telescope.org/nuffield/pas/solar/solar7.html[/url]