  We use the tangent method to compute the arctic curve of the Twenty-Vertex
(20V) model with particular domain wall boundary conditions for a wide set of
integrable weights. To this end, we extend to the finite geometry of domain
wall boundary conditions the standard connection between the bulk 20V and 6V
models via the Kagome lattice ice model. This allows to express refined
partition functions of the 20V model in terms of their 6V counterparts, leading
to explicit parametric expressions for the various portions of its arctic
curve. The latter displays a large variety of shapes depending on the weights
and separates a central liquid phase from up to six different frozen phases. A
number of numerical simulations are also presented, which highlight the arctic
curve phenomenon and corroborate perfectly the analytic predictions of the
tangent method. We finally compute the arctic curve of the Quarter-turn
symmetric Holey Aztec Domino Tiling (QTHADT) model, a problem closely related
to the 20V model and whose asymptotics may be analyzed via a similar tangent
method approach. Again results for the QTHADT model are found to be in perfect
agreement with our numerical simulations.
