The tray was completed and Estee kept writing processing code for 64 switches. We almost ready to use 4 multiplexers. So I started building a circuit with them. Todd said it is better to make resistors fit on the breadboard, we should use pins under the resistors so I put resistors little bit higher. And I put all wires and connected the breadboard to the arduino. It was really hard to maintain all wires on the breadboard because wires were hooked up so easily. If I have a chance to do it again, It would be better to solder all wires on the perfboard.