The irony of trying to plan accidents, and orchestrate their frequent occurrence, is not lost on Mr Williams. So he tries mental tricks. One is to ask “what can we take away to create something new?” A decade ago, you could have started with Yahoo! and taken away all the clutter around the search box to get Google. When he took Blogger and took away everything except one 140-character line, he had Twitter. Radical constraints, he believes, can lead to breakthroughs in simplicity and entirely new things.