Tristan E. O'Tierney BS '08 (computer science) co-founded the popular mobile payment company Square in 2009. Working with Twitter co-founder Jack Dorsey, O'Tierney developed Square's original iPhone application and contributed to the development of Square's iPad application and Square Wallet. 
 
Prior to Square, O'Tierney worked on a variety of Mac-related projects for Silicon Valley powerhouses Yahoo!, VMware and Apple before being contracted to develop the mobile application for President Obama's 2008 campaign. He first caught Co-founder of Twitter Jack Dorsey's attention when he built Twinkle, one of the first ever Twitter client apps.