Simplify the following text for a Grade 2 native English-speaking person.
Original: The pie chart is perhaps the most ubiquitous statistical chart in the business world and the mass media . However , it has been criticized , and some recommend avoiding it , pointing out in particular that it is difficult to compare different sections of a given pie chart , or to compare data across different pie charts .
Simplified: A pie chart is a type of chart with the shape of a pie or circle .