The first thing we've got to consider is that whatever we build, without the cities approval, will likely be torn down as soon as it's spotted. -That said, we can actually use that to attract media attention. Both to the appalling state of homelessness in Portland, but also to government inaction, and even counter-action. -Then point out the fact that we've got new tools to work on it thanks to Needpedia and so many others in the open source community. 

We could make events, classes, where we go 'to location' with the materials, and start teaching people how to build using cob and reused stuff, (like tiny Earthships). -Especially if we could find the means to mechanically stabilize dirt, and to 3D print using waste plastics. This might also be a good opportunity to connect people with cool local organizations like the Village Building Convergence, or even Food not Bombs. 

*We might also be able to find locations where these kinds of structures wouldn't be torn down, (yet would also benefit homeless people). We might also be able to camouflage a few of them closer in for folks who have jobs.

One thing we'll need is an instructor, a truck, building materials, shovels, a tarp (to mix the cob), water, and a bunch of volunteers. -And maybe someone to film it.