  We report a combined theoretical and experimental study on TaIrTe4, a
potential candidate of the minimal model of type-II Weyl semimetals.
Unexpectedly, an intriguing node structure with twelve Weyl points and a pair
of nodal lines protected by mirror symmetry was found by first-principle
calculations, with its complex signatures such as the topologically non-trivial
band crossings and topologically trivial Fermi arcs cross-validated by
angle-resolved photoemission spectroscopy. Through external strain, the number
of Weyl points can be reduced to the theoretical minimum of four, and the
appearance of the nodal lines can be switched between different mirror planes
in momentum space. The coexistence of tunable Weyl points and nodal lines
establishes ternary transition-metal tellurides as a unique test ground for
topological state characterization and engineering.
