boom

local x, z, size = 0, 0, 0

local function eraser(cx, cy, cz)
  cx, cy, cz = cx-(size/2), cy-(size/2), cz-(size/2)
  for ix = 1, size do
    for iy = 1, size do
      for iz = 1, size do
        exec('setblock '..cx+ix..' '..cy+iy..' '..cz+iz..' 0')
      end
    end
  end
end

local function test()
  y = 255
  while y >= (size/2)+5 do
    b, s = exec('testforblock '..x..' '..y..' '..z..' 0')
    if b == false then
      eraser(x, y, z)
      break
    end
    y = y-1
  end
end

function printUsage()
  print('Usage: boom <xCoord> <zCoords> <size>')
  return
end

local tArgs = {...}
if #tArgs == 3 then
  x = tArgs[1]
  z = tArgs[2]
  size = tArgs[3]
  test()
else printUsage()
end