{
  "@context": {
    "ex": "http://example.com/",
    "foo": {"@id": "http://example.com/foo", "@container": "@list"}
  },
  "@graph": [
    {"foo": ["bar"]},
    {
      "@graph": [
        {"ex:foo": "foo"},
        {"ex:bar": "bar"}
      ]
    }
  ]
}