I'll give this a go. I have yet to try the sine cosine so hopefully it'll do the trick. A sweep would work, but I'd like to circle the circumference of its motion zone to ensure it theres nothing restricting movement.

Gee -- it took an awfully long time to get that explanation

Now that I understand it I can make sense of what you said in your Original Post.

Would this general idea work?

Leave one servo at its mid point (90) and move the other servo fully "south" (180) (Using the compass points for simplicity).

Then sweep both servos in small steps with the one that is "south" moving up to the mid point and the other one moving from the mid point to (say) full West. In very simple terms, with code like this

`for (byte n = 0; n <= 90 ; n++) {`

servoNorthSouth.write(180 - n);

servEastWest.write(90 + n);

delay(100);

}

Or is that just too simple?

EDIT to add - yes it is too simple. It would just move in a diagonal....R