public Map<Integer, Column<V>> columnsMap() {
		Map<Integer, Column<V>> columnsMap =
			LazyMap.lazyMap(new HashMap<>(), c -> new Column<V>(c));

		Set<Entry<V, GridPoint>> entrySet = vertexPoints.entrySet();
		for (Entry<V, GridPoint> entry : entrySet) {
			V v = entry.getKey();
			GridPoint gridPoint = entry.getValue();
			int colIndex = gridPoint.col;
			Column<V> col = columnsMap.get(colIndex);
			col.setRow(v, gridPoint.row);
		}
		return columnsMap;
	}
Returns a mapping or column indexes to Column objects in this grid

@return the columns in this grid
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/GridLocationMap.java