sdd:Edge
An sdd:Edge is a scene instance depicting one fact — a triple — as a connection between two sdd:Node instances. Its sdd:depicts object is a quoted triple (RDF-star), not a plain resource, since what the edge grounds is the relationship itself.
An edge owns its connection rather than deferring to node geometry (spec §4.4, examples decision 9): each end is an anchor — a border plus an offset relative to its node's boundary, held by sdd:fromAnchor and sdd:toAnchor — so the connection holds by construction when either node moves. An optional route pins interior waypoints only; the renderer always closes the path from anchor to waypoints to anchor. Edges are always separate stanzas, never lines on a node, and are always children of a sdd:LocalScope or other scope, never of the nodes they connect.