This example shows a force-directed network layout of seven nodes and eight links grouped into overlapping rectangular clusters using WebCola, a constraint-based layout library. The nodes and groups are rendered as SVG rectangles with labels and color-coded fills, while links appear as thick lines. Users can drag nodes to rearrange them, with double-clicking releasing a node from its fixed position. The visualization uses WebCola's `d3adaptor` with `avoidOverlaps` and `linkDistance` settings, integrated with D3 v4's zoom and drag behavior on an SVG container.