The Bard's Tale IV: Director's Cut

You need to use the code wheel to select the correct items for the “Offering Altar” and present them. You will find the first altar near the entrance to Lower Skara Brae. At the beginning of the game, an offering of cabbage and a barrel (needs to be created) is always required there. For other altars, you need to use the encryption wheel from the developers' website , and the decryption book, located on the 2nd floor in the old guild building. After which you need to combine the symbols on the statue with the phase of the moon on the wheel, you will receive two numbers that you need to find in the book.

You can also use this decoder if you don't want to bother with the official wheel and book.