how to drop the second curly bracket?

Flatten /@ (Join @@ vtable)

{{0, 0}, {0, 1}, {1, 0}, {1, 1}}

ArrayReshape[vtable, {4, 2}]

{{0, 0}, {0, 1}, {1, 0}, {1, 1}}

Join @@ vtable /. {a_} :> a

{{0, 0}, {0, 1}, {1, 0}, {1, 1}}

MapAt[Sequence @@ # &, vtable, {{All, All, -1}, {1}, {2}}]

{{0, 0}, {0, 1}, {1, 0}, {1, 1}}

Try with:

Flatten /@ Flatten[vtable, 1]

{{0, 0}, {0, 1}, {1, 0}, {1, 1}}

 vtable /. {x_, {y_}} :> {x, y} // Flatten[#, 1] &

{{0, 0}, {0, 1}, {1, 0}, {1, 1}}

Related