Yesterday he told me: "....1.Tomorrow is not Sunday. 2. Neither it was yesterday. 3.Day after tomorrow is neither Saturday nor Sunday. 4.Yesterday it was neither Monday nor Wednesday. 5.The day before yesterday was not a Wednesday and tomorrow will not be Tuesday. 6.And Today is not Wednesday as well..."
If you draw a grid on which x axis is weekdays from monday to sunday and y axis is from day day before yesterday to tomorrow. Then the only diagonal free is DDBY- Fri, DBY-Sat, Y-Sun, Today - Mon and To- Tue.