Tristan O'Tierney, a Square co-founder who created the company's first mobile app, dies at age 35 from causes likely related to addiction (Shwanika Narayan/San Francisco Chronicle)

Shwanika Narayan / San Francisco Chronicle:
Tristan O'Tierney, a Square co-founder who created the company's first mobile app, dies at age 35 from causes likely related to addiction  —  Tristan O'Tierney, a co-founder of San Francisco payments company Square, died Feb. 23 in Ocala, Fla., of causes related to addiction, his family said.