Hacker News on 4 July 2015

• Greece
• How I’d redesign piano sheet music
• Many Bitcoin wallets vulnerable to double-spending of confirmed transactions
• Show HN: Trigrad, a novel image compression with interesting results
• Show HN: Silicon Valley Dictionary – Urban Dictionary Meets Silicon Valley
• Golang data structures
• The Anti-Mac Interface (1996)
• How I met my identity thief
• The physics of floating screwdrivers [video]
• Elasticsearch: The Definitive Guide