Players have the opportunity to execute the last action they used (attack, support, send resources and send spy) with the same units and resources immediately.
The "last formation" function can only be used if an action has already been used and the same amount of units and resources are available in the currently selected castle. The "last formation” function will not be shown otherwise.
The formation will only take the unit types (as well as their amount) and the selection of resources (as well as their amount) into account that have participated in the last action. Silver for attacks is also taken into consideration.
U.S. Patent Protection US 9,513,766 B2