How give B(10,20) of matrix B black color?

How can I am give B(10,20) of matrix B black color? when using mesh(), or surf(),to plot matrix B

Answer 1

[dpb]

B(10,20,:)=0;

[dpb]

this comment not helping determine what is problem

[Image Analyst]

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer