var a[10, 100, 100]; 
a[0, 0, 0] = 1; // assign 1 to [0, 0, 0]
a[0, 0, 1] = 2; // assign 2 to [0, 0, 1]
…
a[9, 99, 99] = 99999; // assign 99999 to [9, 99, 99]
var b = ::Math.Ave(a); // returns the average of the third dimension elements of a
// (i.e. it returns a 10x100 2D array)
var d = ::Math.Ave(b); // Returns the average of the second dimension elements of b
// (i.e. returns a one-dimensional array of 10 elements)