Create a 4-digit decimal counter by connecting four BCD counters together so that each digit increments at the correct time (D0 should increment at every clock edge, D1 should increment each time D0 reaches 9, D2 should increment each time D1 and D0 reach 9, and D3 should increment only when D0, D1 and D2 all reach 9). Then, build a 4-digit seven-segment controller system using a 4:1 4-bit bus mux, 2:4 decoder, and 2-bit counter. Connect the 4-digit decimal counter outputs to the seven-segment display controller, drive the counter from the 1KHz clock, and verify the counter counts through its range every 10s.