This simple circuit is composed by a clock, D Flip Flops, a 4-bit counter, a button and two hexadecimal displays.

The left D flip flop divides the clock speed by 2. The counter increments at this lower speed. The left hexadecimal display shows the current output of the counter. The right D flip flop saves the output of the left one when the button is pressed. The right hexadecimal display shows the output of the right flip flop.