Size Restrictions on a battle map

The 5-foot gridded battle map method of conducting combat will be common. When using a battle map distances and sizes and shapes are important. For example, if a creature is polymorphed into a huge creature, large creatures in adjacent spaces will be permitted to chose to which adjacent square they are pushed out of the way (note that medium or smaller creatures would not be forced out since they can occupy the same space). But if there is no where for the creaures to be pushed, the polymorph fails. Conjurations can not occur in an occupied space unless the spell says the conjuration is tiny or does not occupy its space. Conjurations will not push creatures out of the way -- instead that conjured creature is just not conjured.