tab_headers (t, 1, 0, 1, 0);
tab_box (t, TAL_1, TAL_1, -1, -1, 0, 0, nc - 1, dsc->var_cnt);
tab_box (t, -1, -1, -1, TAL_1, 1, 0, nc - 1, dsc->var_cnt);
tab_hline (t, TAL_2, 0, nc - 1, 1);
tab_vline (t, TAL_2, 1, 0, dsc->var_cnt);
tab_headers (t, 1, 0, 1, 0);
tab_box (t, TAL_1, TAL_1, -1, -1, 0, 0, nc - 1, dsc->var_cnt);
tab_box (t, -1, -1, -1, TAL_1, 1, 0, nc - 1, dsc->var_cnt);
tab_hline (t, TAL_2, 0, nc - 1, 1);
tab_vline (t, TAL_2, 1, 0, dsc->var_cnt);