Inkscape Tutorial: Create a Teardrop Vector (Episode #35) @ Ardent Designs
http://www.youtube.com/watch?v=RNM5hU2Zi5w
http://www.youtube.com/watch?v=RNM5hU2Zi5w
http://www.youtube.com/watch?v=Noy1dh8-_vQ
https://www.youtube.com/watch?v=xehE0y3WqnA
https://www.youtube.com/watch?v=nPrCcqr-2UM