1.1. LEGAL OFFENSIVE FORMATION
Offensive formation is seen as "legal" when:
a) It has all 11 players assigned
b) Has exactly 1 quarterback c) Has at least 7 men on the line of scrimmage
d) Has exactly 1 center and at least 2 players that are assigned a position of either guard or tackle
e) Does not have more than 1 guard (for each side), tackle (for each side), tight end (for each side), halfback (for each available position) and fullback (for each available position). To explain: You can have 3 halfbacks if they are halfback (right), halback (center) and halfback (left). However, you cannot have 2 or 3 halfbacks (center)
f) Does not have more than 2 wide receivers (for each side)
g) Has at least 1 running back of any type and on any position

1.2. LEGAL DEFENSIVE FORMATION
Defensive formation is seen as "legal" when:
a) It has all 11 players assigned
b) Has at least 2 men on the line of scrimmage
c) Does not have more than 1 nose tackle, tackle (for each side), end (for each side), outside linebacker (for each side), strong safety (for each available position) and free safety (for each available position).
d) Does not have more than 4 middle linebackers
e) Does not have more than 2 cornerbacks (for each side)