$ gem install mason

$ mason buildpacks
* buildpacks (~/.mason/buildpacks)
  = nodejs: https://github.com/heroku/heroku-buildpack-nodejs.git
  = ruby: https://github.com/ddollar/heroku-buildpack-ruby.git

$ mason buildpacks:install https://github.com/heroku/heroku-buildpack-python.git
* installing buildpack https://github.com/heroku/heroku-buildpack-python.git

$ mason build /tmp/app
* detecting buildpack... done
  = name: Ruby
  = url: https://github.com/heroku/heroku-buildpack-ruby.git
* compiling:
... COMPILE OUTPUT
* packaging... done
  = type: dir
  = file: /tmp/mason.out

$ mason build /tmp/app -t dir -o /tmp/compiledapp
* detecting buildpack... done
  = name: Ruby
  = url: https://github.com/heroku/heroku-buildpack-ruby.git
* compiling...
... COMPILE OUTPUT
* packaging... done
  = type: dir
  = dir: /tmp/compiledapp

$ mason build /tmp/app -b https://github.com/ddollar/buildpack-other.git -t tgz
* detecting buildpack... done
  = name: Other
  = url: https://github.com/ddollar/buildpack-other.git
* compiling...
... COMPILE OUTPUT
* packaging... done
  = type: tgz
  = file: /tmp/app.tgz

$ gem install vagrant

$ vagrant box add lucid64 https://files.vagrantup.com/lucid64.box

$ mason stacks:create lucid64
* creating stack lucid64... done

$ mason stacks:up lucid64
* booting stack lucid64 (this may take a while)... done

$ mason:build /tmp/app -t tgz -o /tmp/compiled.tgz -s lucid64
* booting stack lucid64 (this may take a while)... done
* detecting buildpack... done
  = name: Baz
  = url: https://github.com/ddollar/buildpack-baz.git
* compiling...
... COMPILE OUTPUT
* packaging... done
  = type: tgz
  = dir: /tmp/compiled.tgz