function [vertices, faces] = calcBlock(r, R, Lx, Ly, Lz)
% Return vertices and faces of a block geometry

vertices_0 = [
    0,   0,  0;  % #1
    Lx,  0,  0;  % #2
    0,  Ly,  0;  % #3
    0,   0, Lz;  % #4
    Lx, Ly,  0;  % #5
    0,  Ly, Lz;  % #6
    Lx,  0, Lz;  % #7
    Lx, Ly, Lz]; % #8

vertices = r' + vertices_0*R';

faces = [
    1, 2, 5, 3;  % #1
    1, 3, 6, 4;  % #2
    1, 4, 7, 2;  % #3
    4, 7, 8, 6;  % #4
    2, 5, 8, 7;  % #5
    3, 6, 8, 5]; % #6

end