  In the present paper, we obtain explicit formulae for geodesics in some
left-invariant sub-Finsler problems on Heisenberg groups $\mathbb{H}_{2n+1}$.
Our main assumption is the following: the compact convex set of unit velocities
at identity admits a generalization of spherical coordinates. This includes
convex hulls and sums of coordinate 2-dimensional sets, all left-invariant
sub-Riemannian structures on $\mathbb{H}_{2n+1}$, and unit balls in
$L_p$-metric for $1\le p\le\infty$. In the last case, extremals are obtained in
terms of incomplete Euler integral of the first kind.
