Rich. I have taken your complex math SUBs (complex.b) and created a SUBmod (complex.o) via ACE's -m switch (actually, I used ACE:bin/module, by typing 'module complex'). This object module must be linked with any program wishing to use your complex math functions. The provided make script file does this. The only extra thing required is complex.h which declares the SUBs as external to the current source file, declares the complex STRUCT and opens the necessary libraries (don't really need mathtrans yet, but may do later). To check all this out, type: make mandel and run the created 'mandel' program. I've also converted your more recent program to use the SUBmod and called it 'fractal.b'. I like it! Much slower than 'mandel' but nice. Then, see what I've done in complex.b and complex.h. I'll be interested in your feedback and/or questions. Rgds, DB 19th September 1995