diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/NodeSections.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/NodeSections.java
index 487709ba19..33d94616e8 100644
--- a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/NodeSections.java
+++ b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/NodeSections.java
@@ -57,10 +57,11 @@ public RelateNode createNode() {
     while (i < sections.size()) {
       int blockSize = 1;
       NodeSection ns = sections.get(i);
+      //-- are there multiple polygon sections incident at node?
       if (ns.isArea() && hasMultiplePolygonSections(sections, i)) {
         List<NodeSection> polySections = collectPolygonSections(sections, i);
-        List<NodeSection> nsInvert = PolygonNodeConverter.convert(polySections);
-        node.addEdges(nsInvert);
+        List<NodeSection> nsConvert = PolygonNodeConverter.convert(polySections);
+        node.addEdges(nsConvert);
         blockSize = polySections.size();
       }
       else {
diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/PolygonNodeConverter.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/PolygonNodeConverter.java
index 84f9ed9652..5ac07f6580 100644
--- a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/PolygonNodeConverter.java
+++ b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/PolygonNodeConverter.java
@@ -27,16 +27,16 @@
  * which all lies inside the polygon
  * (i.e. they does not enclose hole edges).
  * This allows a simple area-additive semantics to be used
- * for adding edges and propagating edge locations
- * in {@link RelateNode}.
+ * in {@link RelateNode}
+ * for adding edges and propagating edge locations.
  * <p>
- * The arrangement of shells and holes must be topologically valid.
- * I.e. the node sections must not cross.
  * The input node sections are assumed to have canonical orientation
  * (CW shells and CCW holes).
+ * The arrangement of shells and holes must be topologically valid.
+ * Specifically, the node sections must not cross or be collinear.
  * <p>
  * This also supports multiple shell-shell touches 
- * (including ones containing holes) and hold-hole touches, 
+ * (including ones containing holes), and hole-hole touches, 
  * This generalizes the relate algorithm to support
  * both the OGC model and the self-touch model.
  * 
diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyBuilder.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyBuilder.java
index 8c5bf41952..7c635c2300 100644
--- a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyBuilder.java
+++ b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyBuilder.java
@@ -151,7 +151,7 @@ public void finish() {
     predicate.finish();
    }
 
-  private NodeSections getNode(Coordinate nodePt) {
+  private NodeSections getNodeSections(Coordinate nodePt) {
     NodeSections node = nodeMap.get(nodePt);
     if (node == null) {
       node = new NodeSections(nodePt);
@@ -170,10 +170,10 @@ public void addIntersection(NodeSection a, NodeSection b) {
     addNodeSections(a, b);
   }
 
-  private void addNodeSections(NodeSection e0, NodeSection e1) {
-    NodeSections node = getNode(e0.nodePt());
-    node.addNodeSection(e0);
-    node.addNodeSection(e1);
+  private void addNodeSections(NodeSection ns0, NodeSection ns1) {
+    NodeSections sections = getNodeSections(ns0.nodePt());
+    sections.addNodeSection(ns0);
+    sections.addNodeSection(ns1);
   }
   
   private void updateABIntersection(NodeSection a, NodeSection b) {