The chart below shows a breakdown of the units in the Spartan Army. The total size of the army changed from time to time but the example below is a typical representation.
The smallest unit (Enomotia) had 36 men who could be formed into three files (columns) of a rank of twelve men (rows). A Pentecostys made a unit of twelve by twelve. A typical battle unit, the Mora, could made up a Phalanx of twenty four hoplites across and forty eight hoplites deep.
By carrying the command structure down to the level of 36 men, the Spartans could react quickly to changing battle requirements. When tactics required a sudden reversal of position, the commanders could react immediately rather than waiting for instructions from above.