A new packet tensor is described by its packet data, beta, interpolation value and creation precision. Its entry routine computes the local kernel and affine coefficient directly; it does not call the entry routines of the retained old tensors. Those remain separate vertices with their original descriptions. Store all older descriptions immutably by reference. On later calls, evaluate a retained tensor only at its own creation precision, then lift the same coordinate representatives. Thus neither descriptions nor entry routines repeatedly substitute into earlier routines as depth increases. Only polynomially much new description data is added along a path.