To help someone quickly see the post. The posts itself is used to determine where the ball exited the field, across the goal line or touch line.
In football, a standard match requires four compulsory corner flags, one at each corner of the pitch. These flags must be at least 1.5 meters high and clearly visible. The presence of corner flags helps to define the playing area and indicates the corners from which corner kicks can be taken.
4 corner flags. 2 linesmen offside flags.
no need for corner posts
Those who have triangular flags have won the FA cup. any one can use any shape of flag as long as you have a flag on top of corner pole - many clubs use Pennant style or Moon Flags to make them stand out you do not need to have won a cup or league competition
blue and gold
The only official flags associated with soccer are the four corner flags. The Laws of the Game (LOTG), specifically Law 1, do not prescribe a specific size for the cloth on the flags. The corner flag poles must be at least 1.5m (5 ft) tall with a non-pointed top.
foxfinearts.com
they help show whether the ball went out for a corner kick or throw in
a posts tamp
Triangular corner flags are given to winners of the FA Cup. Cardiff City beat Arsenal 1-0 in 1927 and are the only welsh team (so far) to have won the trophy.
The battery posts are located in the lower right hand corner as you face the engine. It is under the windshield fluid container.. on the side of the battery!
The flags (banderas) of the nations of the Caribbean, Central America and South below, with a blue patch in the top corner containing a white five-pointed star.