In mathematics and programming, there exist "order of operations" standards for interpreting expressions. Does something similar exist in US government documents? In particular, I am wondering about seemingly ambiguous instructions in Form I-130 (Petition for Alien Relative) from US Citizenship and Immigration Services. It states:
You have to prove that there is a family relationship between you and the beneficiary. If you are filing for a relative listed below, submit the following documentation to prove the family relationship.
A. A spouse
(1) A copy of your marriage certificate;
(2) If either you were or your spouse was previously married, submit copies of documents showing that each of the prior marriages was legally terminated; and
(3) You must submit two identical color passport-style photographs of yourself and your spouse (if he or she is in the United States) taken within 30 days of filing this petition. The photos must have a white to off-white background, be printed on thin paper with a glossy finish, and be unmounted and unretouched. The two identical color passport-style photos must be 2 by 2 inches. The photos must be in color with full face, frontal view on a white to off-white background. Head height should measure 1 to 1 3/8 inches from top of hair to bottom of chin, and eye height is between 1 1/8 to 1 3/8 inches from bottom of photo. Your head must be bare unless you are wearing headwear as required by a religious denomination of which you are a member. Using a pencil or felt pen, lightly print your name and A-Number (if any) on the back of the photo.
[It goes on to list other documentation that should be provided, if available, to help "prove you have a bona fide marriage."]
Does this mean "(two identical color passport-style photographs) of yourself and your spouse" or "two identical color passport-style photographs of (yourself and your spouse)"? In other words, does this describe two identical photos of each person, for a total of 4 photos? Or is this two identical photos, in which both people appear together, for a total of 2 photos?
And, more generally, are such seeming ambiguities common in official documents?