I have taken Anders Perrson's text files for the Turtlegraphics Unit
and transferred them (with some difficulty) and
compiled/assembled/linked them.
They are available on ftp.whtech.com under /Pascal and on the UCSD
Yahoo! group at:
<http://groups.yahoo.com/group/UCSDPascal/files/TI/turtlegr.zip>

The zip contains a PC99 disk (which can be translated with TI99-PC
found on ftp.whtech.com under /Utils). This disk contains a new
SYSTEM.LIBRARY with the unit included plus many that Anders added to
the standard library. It also has a dozen test programs (some that
require extra hardware and units not provided).

This unit adds the UCSD Turtlegraphics to the 99/4A using bitmap mode.
Read the README.TEXT file on the disk for more information. All the
original source code is included.

Ben