>

restart;

>	a:=2;b:=5;c:=sqrt(a^2+b^2);

>

s:=3*t;

>	with(plots);

Warning, the name changecoords has been redefined

>	z:=a*sin(t);r:=c+a*cos(t);

>	x:=r*cos(s);y:=r*sin(s);

>	tubeplot([x,y,z],t=0..2*Pi,scaling=constrained,grid=[50,50]);

>