diff --git a/src/main/java/pythagoras/f/Crossing.java b/src/main/java/pythagoras/f/Crossing.java
index eeb089d..66e4548 100644
--- a/src/main/java/pythagoras/f/Crossing.java
+++ b/src/main/java/pythagoras/f/Crossing.java
@@ -4,6 +4,9 @@
 
 package pythagoras.f;
 
+/**
+ * Internal utility methods for computing intersections and containment.
+ */
 class Crossing
 {
     /** Return value indicating that a crossing was found. */
@@ -850,13 +853,9 @@ class Crossing
         return UNKNOWN;
     }
 
-    /**
-     * Allowable tolerance for bounds comparison
-     */
+    /** Allowable tolerance for bounds comparison */
     protected static final float DELTA = 1E-5f;
 
-    /**
-     * If roots have distance less then <code>ROOT_DELTA</code> they are double
-     */
+    /** If roots have distance less then <code>ROOT_DELTA</code> they are double */
     protected static final float ROOT_DELTA = 1E-10f;
 }
diff --git a/src/main/java/pythagoras/f/FlatteningPathIterator.java b/src/main/java/pythagoras/f/FlatteningPathIterator.java
index 162d38a..82c0152 100644
--- a/src/main/java/pythagoras/f/FlatteningPathIterator.java
+++ b/src/main/java/pythagoras/f/FlatteningPathIterator.java
@@ -6,88 +6,11 @@ package pythagoras.f;
 
 import java.util.NoSuchElementException;
 
-public class FlatteningPathIterator implements PathIterator
+/**
+ * A path iterator that flattens curves.
+ */
+class FlatteningPathIterator implements PathIterator
 {
-    /**
-     * The default points buffer size
-     */
-    private static final int BUFFER_SIZE = 16;
-
-    /**
-     * The default curve subdivision limit
-     */
-    private static final int BUFFER_LIMIT = 16;
-
-    /**
-     * The points buffer capacity
-     */
-    private static final int BUFFER_CAPACITY = 16;
-
-    /**
-     * The type of current segment to be flat
-     */
-    int bufType;
-
-    /**
-     * The curve subdivision limit
-     */
-    int bufLimit;
-
-    /**
-     * The current points buffer size
-     */
-    int bufSize;
-
-    /**
-     * The inner cursor position in points buffer
-     */
-    int bufIndex;
-
-    /**
-     * The current subdivision count
-     */
-    int bufSubdiv;
-
-    /**
-     * The points buffer
-     */
-    float buf[];
-
-    /**
-     * The indicator of empty points buffer
-     */
-    boolean bufEmpty = true;
-
-    /**
-     * The source PathIterator
-     */
-    PathIterator p;
-
-    /**
-     * The flatness of new path
-     */
-    float flatness;
-
-    /**
-     * The square of flatness
-     */
-    float flatness2;
-
-    /**
-     * The x coordinate of previous path segment
-     */
-    float px;
-
-    /**
-     * The y coordinate of previous path segment
-     */
-    float py;
-
-    /**
-     * The tamporary buffer for getting points from PathIterator
-     */
-    float coords[] = new float[6];
-
     public FlatteningPathIterator (PathIterator path, float flatness) {
         this(path, flatness, BUFFER_LIMIT);
     }
@@ -119,23 +42,51 @@ public class FlatteningPathIterator implements PathIterator
         return bufLimit;
     }
 
+    @Override
+    // from interface PathIterator
     public int getWindingRule () {
         return p.getWindingRule();
     }
 
+    @Override
+    // from interface PathIterator
     public boolean isDone () {
         return bufEmpty && p.isDone();
     }
 
-    /**
-     * Calculates flat path points for the current segment of the source shape. Line segment is
+    @Override
+    // from interface PathIterator
+    public void next () {
+        if (bufEmpty) {
+            p.next();
+        }
+    }
+
+    @Override
+    // from interface PathIterator
+    public int currentSegment (float[] coords) {
+        if (isDone()) {
+            throw new NoSuchElementException("Iterator out of bounds");
+        }
+        evaluate();
+        int type = bufType;
+        if (type != SEG_CLOSE) {
+            coords[0] = px;
+            coords[1] = py;
+            if (type != SEG_MOVETO) {
+                type = SEG_LINETO;
+            }
+        }
+        return type;
+    }
+
+    /** Calculates flat path points for the current segment of the source shape. Line segment is
      * flat by itself. Flatness of quad and cubic curves are evaluated by the getFlatnessSq()
      * method. Curves are subdivided until current flatness is bigger than user defined value and
      * subdivision limit isn't exhausted. Single source segments are translated to a series of
      * buffer points. The smaller the flatness the bigger the series. Every currentSegment() call
      * extracts one point from the buffer. When a series is completed, evaluate() takes the next
-     * source shape segment.
-     */
+     * source shape segment. */
     protected void evaluate () {
         if (bufEmpty) {
             bufType = p.currentSegment(coords);
@@ -232,25 +183,51 @@ public class FlatteningPathIterator implements PathIterator
         }
     }
 
-    public void next () {
-        if (bufEmpty) {
-            p.next();
-        }
-    }
+    /** The type of current segment to be flat */
+    private int bufType;
 
-    public int currentSegment (float[] coords) {
-        if (isDone()) {
-            throw new NoSuchElementException("Iterator out of bounds");
-        }
-        evaluate();
-        int type = bufType;
-        if (type != SEG_CLOSE) {
-            coords[0] = px;
-            coords[1] = py;
-            if (type != SEG_MOVETO) {
-                type = SEG_LINETO;
-            }
-        }
-        return type;
-    }
+    /** The curve subdivision limit */
+    private int bufLimit;
+
+    /** The current points buffer size */
+    private int bufSize;
+
+    /** The inner cursor position in points buffer */
+    private int bufIndex;
+
+    /** The current subdivision count */
+    private int bufSubdiv;
+
+    /** The points buffer */
+    private float buf[];
+
+    /** The indicator of empty points buffer */
+    private boolean bufEmpty = true;
+
+    /** The source PathIterator */
+    private PathIterator p;
+
+    /** The flatness of new path */
+    private float flatness;
+
+    /** The square of flatness */
+    private float flatness2;
+
+    /** The x coordinate of previous path segment */
+    private float px;
+
+    /** The y coordinate of previous path segment */
+    private float py;
+
+    /** The tamporary buffer for getting points from PathIterator */
+    private float coords[] = new float[6];
+
+    /** The default points buffer size */
+    private static final int BUFFER_SIZE = 16;
+
+    /** The default curve subdivision limit */
+    private static final int BUFFER_LIMIT = 16;
+
+    /** The points buffer capacity */
+    private static final int BUFFER_CAPACITY = 16;
 }