Suppose the entire n-brownie (meaning: n-dimensional brownie) is the unit cube [0,1]^n, and the volume *not* containing any end pieces is the inner cube [x, 1-x]^n. Then the crossover point is where (1-2x)^n = 1 - (1-2x)^n, i.e., where 1 - 2x = 1/2^(1/n), or x = (1 - 1/2^(1/n))/2. I think a pretty case is where x = 1/3. For x = 1/3 we have 3^n = 2 so n = log_3(2). I think that would be my favorite brownie. —Dan