David D. Thornburg Related books Beyond turtle graphics Addison-Wesley • 1986 Brainstorms and Lightning Bolts: Thinking Skills for the 21st Century Starsong Pubns • 1999 Discovering Apple Logo: An Invitation to the Art and Pattern of Nature (Addison-Wesley microcomputer books popular series) Addison-Wesley • 1983 Exploring Logo without a computer Addison-Wesley • 1984