NOTE: design these circuits using cell based method, which is very convenient to reuse cells you designed before.
Taking the following design as an example, if you want to implement out = ( in1 & in2) xor (in3 & in4)
1. Draw the schematic of AND, XOR gates, and simulate them respectively. (Fig1)
2. Create symbols to AND and XOR. (Fig2)
3. Using your AND and XOR gates to create the top design, which will implement function out = ( in1 & in2) xor (in3 & in4). (Fig 3)