anchor.diff:        )
       );
       if (config.type == MaterialType.circle) {
  -      contents = new PhysicalModel(
  -        shape: BoxShape.circle,
  -        elevation: config.elevation,
  -        color: backgroundColor,
  -        child: contents,
  -      );
  -    } else if (config.type == MaterialType.transparency) {
  -      if (radius == null) {
  -        contents = new ClipRect(child: contents);
  -      } else {
  -        contents = new ClipRRect(
  -          borderRadius: radius,
  -          child: contents
  -        );
  -      }
  -    } else {
  -      contents = new PhysicalModel(
  -        shape: BoxShape.rectangle,
  -        borderRadius: radius ?? BorderRadius.zero,
  -        elevation: config.elevation,
  -        color: backgroundColor,
  -        child: contents,
  +      contents = new ClipOval(child: contents);
  +    } else if (kMaterialEdges[config.type] != null) {
  +      contents = new ClipRRect(
  +        borderRadius: radius,
  +        child: contents
         );
       }
       if (config.type != MaterialType.transparency) {
  
positive.code: import 'package:flutter/widgets.dart';
  
  import 'constants.dart';
  import 'theme.dart';
  
  /// Signature for the callback used by ink effects to obtain the rectangle for the effect.
  
negative.code:         child: new Container(
            decoration: new BoxDecoration(
              borderRadius: radius,
              boxShadow: config.elevation == 0 ? null : kElevationToShadow[config.elevation],
              backgroundColor: backgroundColor,
              shape: config.type == MaterialType.circle ? BoxShape.circle : BoxShape.rectangle
            ),
  