fluctuations unless a nucleus exceeding a certain critical size is built. Once formed, such an overcritical nucleus will grow relatively fast against the surrounding disordered bulk until it meets another (growing) ordered domain. An $xy$–section of a configuration with overcritical nuclei formed in a system of $128 \times 128\times 128$ fcc–cells is shown in Figs. 2a and 2b. It emerged 7000 MCS after the quench to $T_f=0.972\,T_0>T_{sp}$. The central nucleus seen in the figure is in fact composed of three “twinned” crystallites, corresponding to $\psi_1 \simeq 2$ (the large, nearly homogeneous, bright spot in Fig. 2a) and $\psi_1 \simeq -2$ (the neighboring dark spot). As shown in Fig. 2b, the homogeneous bright spot of Fig. 2a is in fact composed of two crystallites corresponding to $\psi_3 \simeq -2$ and $\psi_3 \simeq 2$, respectively. A second nucleus characterized by $\psi_1 \simeq 2$ and $\psi_3 \simeq -2$ grows at the right edge of the system. The configuration displayed in Figure 2 is quite typical for a quench temperature slightly above $T_{sp}$.

To follow the ordering process that takes place in the whole volume of the system we now introduce an additional quantity [@Fron] $\Phi=(|\psi_1|+|\psi_2|+|\psi_3|)/3$ as a convenient indicator of the degree of 