function iff (x,y,z)
    if a[x][y][z]==1 then
        turtle.select(1)
    elseif a[x][y][z]==2 then
        turtle.select(2)
    elseif a[x][y][z]==3 then
        turtle.select(3)
    elseif a[x][y][z]==4 then
        turtle.select(4)
    elseif a[x][y][z]==5 then
        turtle.select(5)
    elseif a[x][y][z]==6 then
        turtle.select(6)
    elseif a[x][y][z]==0 then
        turtle.select(16)
    end
end

a={
    {
      {0,0,0,1,0,1,0,0} ,
      {0,0,0,0,0,0,0,0} ,
      {0,0,0,1,0,1,0,0} ,
    },
    {
      {0,0,0,2,0,2,0,0} ,
      {0,0,0,2,2,2,0,0} ,
      {0,0,0,2,0,2,0,0} ,
    },
    {
      {0,0,0,2,2,2,0,0} ,
      {1,2,2,2,2,2,0,0} ,
      {0,0,0,2,2,2,0,0} ,
    },
    {
      {0,0,2,0,0,0,0,0} ,
      {0,3,2,0,0,2,3,0} ,
      {0,0,3,0,0,0,0,0} ,
    },
    {
      {0,0,0,0,0,0,0,0} ,
      {0,0,0,0,0,0,0,1} ,
      {0,0,0,0,0,0,0,0} ,
    },
    {
      {0,0,0,0,0,0,0,0} ,
      {0,0,0,0,0,0,0,3} ,
      {0,0,0,0,0,0,0,0} ,
    }
}

turtle.up()
for x = 1, #a do
    for y = 1, #a[x] do
        for z = 1, #a[x][y] do
            iff(x,y,z)
            turtle.placeDown()
            turtle.forward()
        end
        turtle.turnRight()
        turtle.forward()
        turtle.turnRight()
        for y = 1, #a[x][y] do
            turtle.forward()
        end
        turtle.turnRight()
        turtle.turnRight()
    end
    turtle.turnLeft()
    for y = 1, #a[x] do
        turtle.forward()
    end
    turtle.turnRight()
    turtle.up()
end