Plotting family of functions



Somewhere I've seen how to plot a family of functions but I've forgotten
the exact notation.
The following is definitely not correct:

plot2d([block([n], for n:1 thru 3 do (f(x):=sin(n*x)),f(x))],[x,0,2*%Pi]);

but I think you can guess what I intend to do.
What is the correct notation?

Yours,
Poul Riis