{
  "type": "project",
  "input": {
    "type": "service",
    "input": {
      "type": "leftjoin",
      "input": [
        {
          "type": "bgp",
          "patterns": [
            {
              "type": "pattern",
              "termType": "Quad",
              "subject": {
                "termType": "Variable",
                "value": "s"
              },
              "predicate": {
                "termType": "Variable",
                "value": "p"
              },
              "object": {
                "termType": "Variable",
                "value": "o1"
              },
              "graph": {
                "termType": "DefaultGraph",
                "value": ""
              }
            }
          ]
        },
        {
          "type": "service",
          "input": {
            "type": "bgp",
            "patterns": [
              {
                "type": "pattern",
                "termType": "Quad",
                "subject": {
                  "termType": "Variable",
                  "value": "s"
                },
                "predicate": {
                  "termType": "Variable",
                  "value": "p2"
                },
                "object": {
                  "termType": "Variable",
                  "value": "o2"
                },
                "graph": {
                  "termType": "DefaultGraph",
                  "value": ""
                }
              }
            ]
          },
          "name": {
            "termType": "NamedNode",
            "value": "http://invalid.endpoint.org/sparql"
          },
          "silent": true
        }
      ]
    },
    "name": {
      "termType": "NamedNode",
      "value": "http://example1.org/sparql"
    },
    "silent": false
  },
  "variables": [
    {
      "termType": "Variable",
      "value": "s"
    },
    {
      "termType": "Variable",
      "value": "o1"
    },
    {
      "termType": "Variable",
      "value": "o2"
    }
  ]
}