Here are some stories from the past week on TechCrunch Gadgets: What Happened To Kodak’s Moment? Improvement On Age-Old Mathematical Principle Could Yield Improved Images, Video Sea Change: Apple Guts Textbook Publishing Marketing Genius: Two Twins Giggling As They Sell You Designer 3D Glasses What Is A 3D Printer Good For? Stop-Motion Cartoons Featuring Princesses, Of Course!