Open the metal doors by the entrance:
Look right of the door to be opened. Note or write down the position of the black dots seen and on what concentric circles they are on.
Go back to the round structure control panel.
Arrange the black beads to be at the same positions as the black dots seen right of the to be opened metal door. Click on the white circle the beads should be positioned on and the black beads are placed there.
Look down at the base. Note down the position of the gray squares on the panel.
Go back to the metal door to be opened.
Click the squares on top of the metal door to copy the position of the gray squares seen at base of the tower control panel after entering the position of the black circles.
Note that the positions of the sets of squares are in different order from that of the control panel code.
If the gray squares are placed correctly, press the rightmost square to open the door.