sel = {$random} % 35;
if (sel == 6'd0)
begin
#1 force a0.n12 = !a0.n12;
#1 $fdisplay (desc3, "Error at gate #%d | %d | %b",sel, col_in, xtraOut, cout, z1[3], z1[2], z1[1], z1[0], z2[3], z2[2], z2[1], z2[0]);
#1 release a0.n12;
end
else if (sel == 6'd1 )
begin
//node2
#1 force a0.n14 = !a0.n14;
#1 $fdisplay (desc3, "Error at gate #%d | %d | %b",sel, col_in, xtraOut, cout, z1[3], z1[2], z1[1], z1[0], z2[3], z2[2], z2[1], z2[0]);
#1 release a0.n14;
end
else if (sel == 6'd2)
begin
//node3
#1 force a0.n15 = !a0.n15;
#1 $fdisplay (desc3, "Error at gate #%d | %d | %b",sel, col_in, xtraOut, cout, z1[3], z1[2], z1[1], z1[0], z2[3], z2[2], z2[1], z2[0]);
#1 release a0.n15;
end