PREFIX ex: <http://a.example>
PREFIX sx: <http://www.w3.org/ns/shex#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

[] a sx:Schema ;
    sx:shapes (<http://a.example/S1>
        <http://a.example/S2>
        <http://a.example/S3>
        <http://a.example/S4>) .

<http://a.example/S1> a sx:ShapeDecl ; sx:shapeExpr [ a sx:Shape ;
    sx:expression [ a sx:TripleConstraint ;
            sx:predicate <http://a.example/p1> ;
            sx:valueExpr [ a sx:ShapeAnd ;
                    sx:shapeExprs (
                                <http://a.example/S2>
                                <http://a.example/S3>
                                <http://a.example/S4> ) ] ] ] .

<http://a.example/S2> a sx:ShapeDecl ; sx:shapeExpr [ a sx:Shape ;
    sx:expression [ a sx:TripleConstraint ;
            sx:predicate <http://a.example/p2> ] ] .

<http://a.example/S3> a sx:ShapeDecl ; sx:shapeExpr [ a sx:Shape ;
    sx:expression [ a sx:TripleConstraint ;
            sx:predicate <http://a.example/p3> ] ] .

<http://a.example/S4> a sx:ShapeDecl ; sx:shapeExpr [ a sx:Shape ;
    sx:expression [ a sx:TripleConstraint ;
            sx:predicate <http://a.example/p4> ] ] .