3-D or perspective pie charts are popular graphical displays, especially now that they are so easy to produce on computers, but they are problematical because they distort the very features that communicate the information about the data. This paper presents evidence to support the hypothesis that such distortions can lead to mis-information being obtained from such graphs. In particular the orientation of the segments is crucial to the interpretation of the data. This evidence comes from an experiment on a large number of subjects from varied backgrounds and ages who were asked to identify the largest and smallest segments in a 3-D pie chart. For some graphs the numbers of respondents who identified the segments incorrectly far exceeded those who identified them correctly. A control group who carried out the same task for 2-D pie charts were all able to correctly identify the largest and smallest segments in each graph.