Hello! Currently it is not possible to pass shape() of one multi_array into constuctor of another: boost::multi_array<float, 2> a; boost::multi_array<float, 2> b(a.shape()); This is because shape() returns size_t const* and multi_array check in constructor that ExtendList satisfy CollectionConcept. size_t const* don't satisfy this concept. I'm going to allow constructor of multi_array to get both size_t const* and size_t const[]. So I'm going to replace extents.begin() with boost::begin(extents). What should I do with concept check?