Malcom x how did he read during prison at night?

Malcolm x learn how to read in prison, by copying the dictionary, in his autobiography he explains the once he grew acostumed to read he would do it in every free time he would have and whem the light came out in prison, his cell was just near enough a corridor light that allowed him, with the glow of that corridor light, to be seated in the floor near the cell bars and read from there.