Initial data commit

Task/Abstract-type/Fantom/abstract-type.fantom

@@ -0,0 +1,28 @@
+abstract class X
+{
+  Void method1 ()
+  {
+    echo ("Method 1 in X")
+  }
+
+  abstract Void method2 ()
+}
+
+class Y : X
+{
+  // Y must override the abstract method in X
+  override Void method2 ()
+  {
+    echo ("Method 2 in Y")
+  }
+}
+
+class Main
+{
+  public static Void main ()
+  {
+    y := Y()
+    y.method1
+    y.method2
+  }
+}