Prismatic Wings

You acquire a set of retractable wings which
emerge from behind your shoulder blades.
Your wings can propel you anywhere in three
dimensions at your normal movement speed.
To use these wings, you must either jump up
from the ground, or jump off from a point of
elevation. You may remain airborne for two
turns without difficulty. At the beginning of
each of your subsequent turns, you must make
an increasingly difficult SWOLE roll to remain
airborne.