clk: 0, foo: 00
clk: 1, foo: 00
clk: 0, foo: AB
clk: 1, foo: AB
clk: 0, foo: AB
clk: 1, foo: AB
clk: 0, foo: BC
clk: 1, foo: BC
clk: 0, foo: BC
clk: 1, foo: BC
clk: 0, foo: BC
clk: 1, foo: BC
