You will be using three buttons: logic-0, logic-1, and activity button.
At every turn, the player in turn will enter the coordinates sequentially using the logic-0 and logic-1 buttons. Then, the player
should press the activity button.
However, the coordinates should be typed in reverse. That is, the enter order is in LSB (least significant bit) to MSB (most significant bit).
For example, the 5B coordinate corresponds to 1010 1000 instead of 0101 0001.
Example
The triangle player has the turn. If the player wants to place a shape to the 4C coordinate, the player should press the input buttons with the 0010 1100 order.
Notice that the order for entering a character is reversed so that the FPGA reads 0100 0011.
After pressing the activity button, a triangle will be placed if the 4C box is empty. Now, the circle player does the same.