I am making a $4$ bit digital calculator project. I have a problem in mainCircuit. In ALU circuits, there are $10$ pins on the top$(9$th pin has $2$bit and $10$th pin has $1$ bit. The circuit on the top$-$right side of ALU is ControlUnit which has two $1-$bit control pins. On the bottom$-$right side of ALU is OutputInterface which has four $1-$bit pins. When I connect them, the wires turn out blue. What is the problem with them?