tab_text (table, 1, 1 + i * 4, TAB_LEFT, _("Negative Differences"));
tab_text (table, 1, 2 + i * 4, TAB_LEFT, _("Positive Differences"));
tab_text (table, 1, 1 + i * 4, TAB_LEFT, _("Negative Differences"));
tab_text (table, 1, 2 + i * 4, TAB_LEFT, _("Positive Differences"));