He's split his time between these two companies before. "... after 8 hours at Twitter, he literally walks 2 blocks to put in another 8 hour shift at Square."

http://thenextweb.com/entrepreneur/2011/11/14/jack-dorsey-do...

They were much smaller companies (pre public) in 2011 and he was never CEO at both at the same time. Executive Chairman is substantially different.

Only instead of being 500 miles apart, Twitter and Square are closer to 500 feet apart.

Maybe Jack located them close together for a reason.

Actually, we're only about 200 feet building-to-building. Just across 10th street with an apartment/condo building in between.

Square just moved offices to be right next to Twitter, so it shouldn't be too hard for him to go back and forth