Much prettier pie-charts can be created with javascript and CSS.
This is for older folk like me who like BASIC programming.
Enter the following in a tiddler in some TiddlyWiki:
(ignore the triple-backticks; they are just to format the code correctly for TalkTiddlyWiki)
<iframe src="https://basicanywheremachine.neocities.org/sample_programs/Pie%20Chart%20Service.prod.run?SCREEN=17&DATA=12,36,13,12,25,42,30,26,20,49," style="width:250px;height:250px;"> </iframe>
More details in this blog entry.
(By the way, should you actually find this thing useful and you actually like rough-around-the-edges old-school-charm, do save the HTML file and save it where you need it, because my hosted file might not be reliable/stable as a “service”.)