After increasing the maximum number of slices in pie charts (#1543) there is the problem of repeated colors. To fix this we need to introduce more colors to the pie charts.
Attachment: Suggestion for new pie chart slice colors (based on the HSL values of the current colors). Any comments? Free to commit?
Attachment: This is how the initial pie chart would look with the new colors
pie colors fixed.png
greg: In case you're wondering where the colors are defined, it's in core/Visualization/Chart/Pie.php.