Hacker News on 21 April 2013

• Very Short Reply Expected
• Ruby is too slow for programming competitions
• Cognitive Overhead, Or Why Your Product Isn’t As Simple As You Think
• The Last Question
• What's Tylenol Doing to Our Minds?
• Writing device drivers in Linux: A brief tutorial (2006)
• The Clown Car Technique for Responsive Images
• Show HN: jsdares – learning programming visually
• In India, 'no frills' hospitals offer $800 heart surgery
• Diving into AngularJS