function Shower(power)
  if iter%(-power+4) == 0 then
    sent = CreateProjectileAbs("sentinel", 320, 240)
    sent.SetVar("theta", math.random(360))
    sent.SetVar("ind_iter", 0)
    sent.SetVar("deadly", true)
    sent.SetVar("offset", math.random(90))
    table.insert(sentinels, sent)
    if iter%((-power+4)*3) == 0 then
      Audio.PlaySound("fling")
    end
  end
end

function AttackIter()
  for i=1, #sentinels do
    sent = sentinels[i]
    if sent.isactive then
      AnimateSentinel(sent)
      if sent.GetVar("r") == nil then
        iiter = sent.GetVar("ind_iter")
        sent.SetVar("ind_iter", iiter+2)
        sent.MoveToAbs((iiter*math.cos(sent.GetVar("theta")*math.pi/180))+320, (iiter*math.sin(sent.GetVar("theta")*math.pi/180))+240)
        if iiter > 225 then
          sent.sprite.alpha = (-(iiter-225)+10)/10
        elseif iiter > 235 then
          sent.remove()
        end
	  end
    end
  end