          assert.isTrue(positionEquals(container, 0, 300, 0, 120), "container position ok");
          assert.isTrue(positionEquals(c1, 0, 50, 0, 50), "child 1 position ok");
          assert.isTrue(positionEquals(c2, 0, 50, 50, 100), "child 2 position ok");
          assert.isTrue(positionEquals(c3, 50, 100, 0, 50), "child 3 position ok");
          assert.isTrue(positionEquals(c4, 50, 100, 50, 100), "child 4 position ok");
          assert.isTrue(positionEquals(c5, 100, 150, 0, 50), "child 5 position ok")