Editing Yagura:SRD:Movement, Position, and Distance (section)

====Small Creatures====

Though Small creatures take up one quarter of a square (2-1/2 feet) and 4 Small creatures can fit within a square, Small creatures treat reach somewhat differently than Tiny and smaller creatures. A Small creature's reach being 2-1/2 feet is just enough to function virtually the same as a 5 foot reach as long as the Small creature occupies a square alone. If more than one Small creature occupies a square it forces the Small creatures to occupy a set quadrant of the square, pushing each other to the edges. A Small creature does not have adequate reach to strike an opponent in an adjacent square unless the quadrant of the square they occupy is adjacent. Therefore two halflings could occupy a single square and do battle with a human in an adjacent square, but if a third halfling were to occupy the square with the other two, that third halfling could not strike the human without using a reach weapon. Reach weapons in the hands of Small creatures grant 5 foot reach. A warband of kobolds are likely to carry spears, allowing 4 of them to attack a larger foe from the same square.