The following program causes a Segmentation Fault in UCBLogo 5.6 on Linux:
repeat 60 [ fd 6 rt 6 ]
repeat 50 [ circle ]
Version 5.6 is the latest version I could find for Linux. I got version 5.6 from the Fedora repository, and version 5.6 was also the latest version of source code I was able to find (although when untarred it creates a directory called ucblogo-6.0, the version is listed as 5.6). The above program crashed both the version I got from the repository and the version I compiled myself from source.