{{ Define ortho(a,b,g,p)=when( {p[1]*cos(a)+p[2]*cos(b)+p[3]*cos(g) p[1]*sin(a)+p[2]*sin(b)+p[3]*sin(g)} }} I actually get an error...is it ok if i do this: Define ortho(a,b,g,p)= {p[1]*cos(a)+p[2]*cos(b)+p[3]*cos(g), p[1]*sin(a)+p[2]*sin(b)+p[3]*sin(g)} (one line of course) -Rob