Furthermore, A (t) is just a special case of the set of possible new cells. In general, any invertible matrix whose columns are valid translations (including columns of the identity matrix) is the matrix of a valid cell. The best new cell is the one with the smallest volume, but combinatorial exploration of all possible such matrices that lead to smaller cells has a worst-case complexity of O(n 3 ). In practice, many candidate matrices can be eliminated before computing their determinant so using this method is actually quite efficient.