So I was poking around this subreddit like I do, and I came across some info on how pikemen formed large formation squares surrounding themselves with pikes. and the musket infantries in the Napoleonic era (this was all for the protection against cavalry charges).
But I came across this idea:
squares have corners...
infantry squares have corners...
So, wouldn't it be easy for a cavalry charge to weaken the corners of infantry squares? (because there's less men, rather than a long wall of them like on the sides). So I thought since circles don't have corners, it would be more difficult to penetrate a circled formation of pikes/spears/muskets, rather than an infantry square...
Or am I just wrong?
The main reason why rank-and-file infantry forms squares rather than circles is that the latter are not easily acquired by drilled formations. Unless each soldier knows exactly where he is supposed to be at the end of an evolution, relative to the men in front of him and beside him, there is no guarantee that he will be where you want him to be. Evolutions of a simple rank-and-file formation have to be attainable by wheeling, facing left or right, or countermarching. If a unit tries anything other than these basic formation adjustments, the result will inevitably be chaos.
A square can be easily formed by marching out and wheeling around a pivot. But how would you form a circle? How could you make sure that each man is exactly "slightly to the right and behind but not too far" of the man next to him? There would be no markers on the ground telling people where they are supposed to go...
That said, the Scots are said to have formed a circular schiltrom formation at Falkirk and Bannockburn. This may well have been possible exactly because the troops were not elaborately drilled, and simply contracted in the most efficient way in response to the approach of enemy cavalry.
If it is a circle then only one guy is pointed directly at the attacking force.