{
  "@context": "http://www.w3.org/ns/shex.jsonld",
  "type": "Schema",
  "shapes": [
    { "type": "ShapeDecl",
    "id": "http://a.example/S1",
    "shapeExpr": {
      "type": "Shape",
      "expression": {
        "type": "TripleConstraint",
        "predicate": "http://a.example/p1"
      }
    } },
    { "type": "ShapeDecl",
    "id": "http://a.example/S2",
    "shapeExpr": {
      "type": "Shape",
      "expression": {
        "type": "TripleConstraint",
        "predicate": "http://a.example/p2"
      }
    } },
    { "type": "ShapeDecl",
    "id": "http://a.example/S3",
    "shapeExpr": {
      "type": "Shape",
      "expression": {
        "type": "TripleConstraint",
        "predicate": "http://a.example/p3"
      }
    } },
    { "type": "ShapeDecl",
    "id": "http://a.example/S4",
    "shapeExpr": {
      "type": "Shape",
      "expression": {
        "type": "TripleConstraint",
        "predicate": "http://a.example/p4"
      },
      "extends": [ "http://a.example/S1", "http://a.example/S2", "http://a.example/S3" ]
    } }
  ]
}