Curl({f1, f2}, {x1, x2})

Curl({f1, f2, f3}, {x1, x2, x3})

>>> Curl({f(u,v,w),f(v,w,u),f(w,u,v),f(x)}, {u,v,w})
{-D(f(v,w,u),w)+D(f(w,u,v),v),-D(f(w,u,v),u)+D(f(u,v,w),w),-D(f(u,v,w),v)+D(f(v,w,u),u),f(x)}