  Ideal Weyl points, which are related by symmetry and thus reside at the same
frequency, could promote the deep development and utilization of the Weyl
physics. Although the ideal type-I Weyl points have been achieved in photonic
crystals, the ideal type-II Weyl points with tilted cone-like band dispersions,
are still beyond discovery. Here we realize ideal type-II Weyl points of
minimal number in three-dimensional layer-stacked phononic crystals, and
demonstrate topological phase transition from Weyl semimetal to valley
insulators of two distinct types. The Fermi-arc surface states exist on the
interface of the Weyl and valley phases, while the Fermi-circle ones occur on
that of the two distinct valley phases. We show the interesting wave partition
of Fermi-circle surface states on the interfaces formed by distinct valley
phases.
