  The Nash-Kuiper Theorem states that the collection of $C^1$-isometric
embeddings from a Riemannian manifold $M^n$ into $\mathbb{E}^N$ is $C^0$-dense
within the collection of all smooth 1-Lipschitz embeddings provided that $n <
N$. This result is now known to be a consequence of Gromov's more general
$h$-principle. There have been some recent extensions of the Nash-Kuiper
Theorem to Euclidean polyhedra, which in some sense provide a very specialized
discretization of the $h$-principle. In this paper we will discuss these recent
results and provide generalizations to the setting of isometric embeddings of
spaces endowed with indefinite metrics into Minkowski space. The new
observation is that, when dealing with Minkowski space, the assumption
"1-Lipschitz" can be removed. Thus, we obtain results about isometric
embeddings that are $C^0$-dense within the collection of {\it all} continuous
maps.
