anchor.diff:      padding: pad,
       onPressed: onPressed,
     );
  +}
  +
  +// ==================================================
  +// block
  +
  +Widget block(List<Widget> children) {
  +  return new Block(
  +      children: children,
  +  );
   }
positive.code: }
  
  // ==================================================
  
  Border bottom({
    width: 1.5,
  
negative.code:     ],
    );
  }
  
  // ==================================================
  // input
  
  Widget text_input(String value, InputValueCB cb, {
    num fontSize = FONT_SIZE + INPUT_EXTRA_SIZE,
  