Obtain a primitive flow table for a circuit with two inputs, $x _1 and x _2$ and two outputs $y _1 and y _2$, that satisfy the following four conditions.
- When $x _1x _2 = 00$, the output is $z _1z _2 = 00$.
- when $x _1 = 1$ and $x _2$ changes from 0 to 1, the output is $z _1z _2 = 01$.
- when $x _2 = 1$ and $x _1$ changes from 0 to 1, the output is $z _1z _2$ = 10.
- otherwise the output does not change.