An uncharacteristically friendly clash of the titans took place on Twitter on Sunday afternoon, with Jeff Bezos giving fellow mogul Elon Musk some pointers on the logistics of turning a building into a homeless shelter. A Saturday poll by the Tesla chief executive, who won 9.2 percent of Twitter this week, kicked off the exchange, with Musk asking his followers if they thought Twitter’s San Francisco headquarters should be repurposed “since no one shows up anyway.” (Of the 1.8 million votes his poll had collected as of Sunday afternoon, more than 90 percent of respondents favored the remodeling idea.) Bezos then jumped to suggest Musk “do the part,” combining office space and housing. Not one to miss an opportunity to elaborately self-promote, he added that a similar divisional framework had “worked great” at Amazon’s headquarters in Seattle. Adding a shelter to the campus, the entrepreneur added, “makes it easy for employees who want to volunteer.” Musk grew his personal fortune to $282 billion this year, according to a Forbes list released this week — widening the gap between him and Bezos by more than $100 billion.