  Imposing extendibility on Kasner-Fronsdal black hole local isometric
embedding is equivalent to removing conic singularities in Kruskal
representation. Allowing for globally non-trivial (living in $M_{5}\times
S_{1}$) embeddings, parameterized by $k$, extendibility can be achieved for
apparently forbidden frequencies $\omega_{1}(k)\le\omega (k)\le \omega_{2}(k)$.
The Hawking-Gibbons limit, say $\displaystyle{\omega_{1,2}(0)= {1\over{4M}}}$
for Schwarzschild geometry, is respected. The corresponding Kruskal sheets are
viewed as slices in some Kaluza-Klein background. Euclidean $k$ discreteness,
dictated by imaginary time periodicity, is correlated with twistor flux
quantization.
