If You Have A Powered Piston (Powered Through A Redstone Line) Then Any Update Of Conductivity(How Far The Redstone Source Is From The Piston) To The Redstone Line Powering The Piston Would Cause The Piston To Retract And During The Same Tick, Extend (Both When Source Gets Further Away Or Closer In).

EXAMPLE SETUP

P = Piston, R = Redstone, T = Redstone Torch, B = Block, Bu = Button

P R R R R R R R R R R R R R R T
^ Just A Regular Line Powering The Piston
But If We Do This:
P R R R R R R R R R R R R R R T
------B
------Bu

(Had To Add Dashes As Space Did Not Work The Way It Was Supposed To)

Whenever we Push The Button, The Piston Will Rapidly Toggle When A Button Gets Depressed.
I Found That If The "Additional Source(Source Causing The Piston To Do This)" Is Too Close To The Source, This Does Not Behave This Way.