The 13-year wait for something — anything — to change where the partly built Berkman Plaza 2 tower has hulked in skeletal form on the downtown riverfront finally moved toward demolition Thursday when the first chunk of pulverized concrete came down. The demolition won't deliver the catharsis of an eye-catching implosion leveling a structure in a matter of seconds. The painstaking work using a high-reach excavator will remove pieces of the tower one bite at time over the next three to four months, starting at the top and gradually moving to the ground. City Council member Reggie Gaffney said that after 13 frustrating years, "just to see the first rock crushed, to me it was a very humbling experience and I’m just so excited."