The Cross Target

A curious target wasdesigned by an eccentric sharpshooter.
His idea was that in order to score you must hit four circles in as many shots so that those four shots shall form a square.
It will be seen by the results recorded on the target that two attempts have been successful. 
The first man hit the four circles at the top of the cross, and thus formed his square. 
The second man intended to hit the four in the bottom arm, but his second shot, on the left, went too high. 
This compelled him to complete his four in a different way than he intended. 
It will thus be seen that though it is immaterial which circle you hit at the first shot, the second shot may commit you to a definite procedure if you are to get your square. 

In just how many different ways it is possible to form a square on the target with four shots?

See answer

Math Genius