You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: create_plaza.m
    path of file: ./repos/Mathematical_Modeling/Cellular automaton/元胞自动机/1月13日课件（元胞自动机）/程序/The Booth Tolls for Thee
    
    the code of the file until where you have to start completion: function plaza = create_plaza(B, L)
global plazalength;
topgap = 5;
bottomgap = 1;

    
function plaza = create_plaza(B, L)
global plazalength;
topgap = 5;
bottomgap = 1;
plaza = zeros(plazalength,B+2);
if mod(B-L,2)==0
for row = 1:plazalength
plaza(row,1) = -888;
plaza(row,2+B) = -888;
end