diff --git a/Nested/src/Collection.java b/Nested/src/Collection.java
new file mode 100644
index 0000000..20026e8
--- /dev/null
+++ b/Nested/src/Collection.java
@@ -0,0 +1,92 @@
+public class Collection {
+    public static Integer[] array;
+
+    public Collection(Integer[] args) {
+        this.array = args;
+    }
+    class FirstTaskIterator implements Iterator {
+
+        private int count = 0;
+
+                @Override
+        public boolean hesNext() {
+            return count < array.length;
+        }
+
+        @Override
+        public Integer next() {
+            if ((count % 2) == 0) {
+                return array[count++];
+            }
+            count++;
+            return 0;
+        }
+    }
+
+    class SecondTaskIterator implements Iterator {
+
+        private int count = array.length - 1;
+
+        @Override
+        public boolean hesNext() {
+            return count > 0;
+        }
+
+        @Override
+        public Integer next() {
+            int a;
+            a = array[count];
+            count -= 2;
+            return a;
+        }
+
+    }
+
+    class ThirdTaskIterator implements Iterator {
+
+        private int count = 0;
+
+
+        @Override
+        public boolean hesNext() {
+            return count < array.length;
+        }
+
+        @Override
+        public Integer next() {
+            int a = 0;
+            while (a == 0 && count < array.length) {
+                if ((count + 1) % 5 == 0 && array[count] % 2 == 0) {
+                    a = array[count] - 100;
+                }
+                count++;
+            }
+            return a;
+        }
+    }
+
+    static class FourthTaskIterator implements Iterator {
+
+        private int count;
+
+        @Override
+        public boolean hesNext() {
+            return count < array.length;
+        }
+
+        @Override
+        public Integer next() {
+            int a = 0;
+            while (a == 0 && a < array.length) {
+                if (array[count] % 2 == 0) {
+                    a = array[count] - 1;
+                }
+                count ++;
+            }
+            return a;
+        }
+
+    }
+
+}
+
diff --git a/Nested/src/Iterator.java b/Nested/src/Iterator.java
new file mode 100644
index 0000000..e416ca3
--- /dev/null
+++ b/Nested/src/Iterator.java
@@ -0,0 +1,5 @@
+public interface Iterator {
+    Integer next();
+
+    boolean hesNext();
+}
diff --git a/Nested/src/Main.java b/Nested/src/Main.java
new file mode 100644
index 0000000..872bf63
--- /dev/null
+++ b/Nested/src/Main.java
@@ -0,0 +1,48 @@
+public class Main {
+    public static void main(String[] args) {
+        Collection someCollection = new Collection(new Integer[]{11, 22, 33, 44, 55, 66, 77, 88, 99, 10, 20, 30, 40, 50, 60, 70, 80, 90});
+        Iterator firstTaskIterator = someCollection.new FirstTaskIterator();
+        Iterator secondTaskIterator = someCollection.new SecondTaskIterator();
+        Iterator anonIterator = new Iterator() {
+            private int count = someCollection.array.length - 1;
+
+
+            @Override
+            public boolean hesNext() {
+                return count > 0;
+            }
+
+            @Override
+            public Integer next() {
+                int a = 0;
+                while (a == 0 && count > 0) {
+                    if (someCollection.array[count] % 2 != 0) {
+                        a = someCollection.array[count];
+                    }
+                    count -= 3;
+                }
+                count -= 3;
+                return a;
+            }
+
+
+        };
+        Iterator thirdTaskIterator = someCollection.new ThirdTaskIterator();
+        Iterator fourthTaskIterator = new Collection.FourthTaskIterator();
+
+
+        display(firstTaskIterator);
+        display(secondTaskIterator);
+        display(anonIterator);
+        display(thirdTaskIterator);
+        display(fourthTaskIterator);
+
+    }
+    static void display(Iterator iterator) {
+        while (iterator.hesNext()) {
+            System.out.print(iterator.next() + " ");
+        }
+        System.out.println("\n" + "^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^");
+    }
+}
+