The next mural up is Art Fills the Void!, the giant banana mural at SE 12th & Division. It's not the most elaborate mural in town, and it obviously needs a touch up, but there's a story behind this one. It turns out this banana dates back to 1982, which makes it positively ancient by mural standards. PDX Street Art explains that it was created by a group of artists calling themselves "Gorilla Wallflare", and the banana was meant as a protest against the Reagan-era guerrilla wars raging across Central America.
A Portland Public Art post about it went with the common theory that it's a riff on Andy Warhol's cover art for a 1967 Velvet Underground album. The PDX Street Art article includes an interview with one of the artists, who mentioned Warhol as one of a long list of inspirations, so I imagine there's at least a kernel of truth to the idea.
A September 1982 Oregonian article "Fruit looms on blank wall as first sign of attack on blandness" explains that the building was then home to an office supply company, rather than the assorted hipster businesses it hosts in 2015. Although the banana appeared without the company's involvement, employees immediately fell in love with the thing, and it quickly began showing up in sales presentations and the company newsletter. This undoubtedly helped it survive over 30-odd years. Gorilla Wallflare painted a number of other murals around town during the 80s, but apparently this is the only one left. The others have all been lost to time, the elements, periodic crackdowns by City Hall, and developers' bulldozers.