Manim. How to create a matrix without brackets?

Question

I'm using Manim Community v17.3., defined

B11=Matrix([[3],[4]],left_bracket="\\",right_bracket="\\.")

produces the error :

I tried empty left anr right bracket and there are other errors.LaTeX Font Info:
Trying to load font information for U+msa on input line 9.
(/usr/local/texlive/texmf-dist/tex/latex/amsfonts/umsa.fd
File: umsa.fd 2013/01/14 v3.01 AMS symbols A
)
LaTeX Font Info:    Trying to load font information for U+msb on input line 9.
(/usr/local/texlive/texmf-dist/tex/latex/amsfonts/umsb.fd
File: umsb.fd 2013/01/14 v3.01 AMS symbols B
)
! Missing delimiter (. inserted).
<to be read again> 
                   \begingroup 
l.11 \end{align*}

It is important to me not to simply redefining de color of the bracket to be equal to de background color, because they perturbates other images behind.