diff -r acf2c31e22d4 -r 40cabcdcd2be samples/composition/src-api2.0/org/apidesign/math/Arithmetica.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/samples/composition/src-api2.0/org/apidesign/math/Arithmetica.java	Thu Oct 30 21:30:10 2014 +0100
@@ -0,0 +1,30 @@
+package org.apidesign.math;
+
+/** Class to simplify arithmetical operations, improved version to compute
+ * the sum for ranges.
+ *
+ * @author Jaroslav Tulach <jtulach@netbeans.org>
+ * @version 2.0
+ */
+public class Arithmetica {
+    public int sumTwo(int one, int second) {
+        return one + second;
+    }
+    
+    public int sumAll(int... numbers) {
+        if (numbers.length == 0) {
+            return 0;
+        }
+        int sum = numbers[0];
+        for (int i = 1; i < numbers.length; i++) {
+            sum = sumTwo(sum, numbers[i]);
+        }
+        return sum;
+    }
+    
+// BEGIN: design.composition.arith2.0
+    public int sumRange(int from, int to) {
+        return (from + to) * (Math.abs(to - from) + 1) / 2;
+    }
+// END: design.composition.arith2.0
+}