How can I create a 2 dimensional list?first of all I thank every one who answered me and then As answered, I can have one list in another one, but then how can I reach the elements easily?In fact I want to have something like this:"a[i,j]" and reach the elements around "a[i,j]" and then have the maximum,average,... of them. as you know I can easily reach the maximum by using lists.If there is no way do so,Is there any method in C# that can help me have the maximum,average,... thanks again