Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Cannot be Special Summoned. If this card attacks a Defense Position monster, inflict piercing battle damage. Up to twice per turn, when this attacking card destroys a monster by battle: You can discard 1 Machine monster; this card can attack again in a row. If this card on the field is destroyed by battle or card effect: You can add 1 "Polymerization" from your Deck to your hand, and if you do, add 1 other "Ancient Gear" monster from your GY to your hand.
--古代の機械巨人－アルティメット・パウンド
--Ancient Gear Golem - Ultimate Pound
local s,id=GetID()
function s.initial_effect(c)
	--cannot special summon
	local e1=Effect.CreateEffect(c)
	e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_SPSUMMON_CONDITION)
	c:RegisterEffect(e1)
	--pierce
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_PIERCE)
	c:RegisterEffect(e2)
	--extra attack
	local e3=Effect.CreateEffect(c)
	e3:SetDescription(aux.Stringid(id,0))
	e3:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e3:SetCode(EVENT_BATTLE_DESTROYING)
	e3:SetCountLimit(2)
	e3:SetCondition(s.atcon)
	e3:SetCost(s.atcost)
	e3:SetOperation(s.atop)
	c:RegisterEffect(e3)
	--to hand
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,1))
	e4:SetCategory(CATEGORY_TOHAND+CATEGORY_SEARCH)
	e4:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e4:SetProperty(EFFECT_FLAG_DELAY)
	e4:SetCode(EVENT_DESTROYED)
	e4:SetCondition(s.thcon)
	e4:SetTarget(s.thtg)
	e4:SetOperation(s.thop)
	c:RegisterEffect(e4)
end
s.listed_series={SET_ANCIENT_GEAR}
s.listed_names={CARD_POLYMERIZATION}
function s.atcon(e,tp,eg,ep,ev,re,r,rp)
	return Duel.GetAttacker()==e:GetHandler() and aux.bdcon(e,tp,eg,ep,ev,re,r,rp)
		and e:GetHandler():CanChainAttack(0)
end
function s.costfilter(c)
	return c:IsRace(RACE_MACHINE) and c:IsDiscardable()
end
function s.atcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.costfilter,tp,LOCATION_HAND,0,1,nil) end
	Duel.DiscardHand(tp,s.costfilter,1,1,REASON_DISCARD|REASON_COST)
end
function s.atop(e,tp,eg,ep,ev,re,r,rp)
	Duel.ChainAttack()
end
function s.thcon(e,tp,eg,ep,ev,re,r,rp)
	return (r&REASON_EFFECT+REASON_BATTLE)~=0 and e:GetHandler():IsPreviousLocation(LOCATION_ONFIELD)
end
function s.thfilter1(c)
	return c:IsCode(CARD_POLYMERIZATION) and c:IsAbleToHand()
end
function s.thfilter2(c)
	return c:IsSetCard(SET_ANCIENT_GEAR) and c:IsMonster() and c:IsAbleToHand()
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.thfilter1,tp,LOCATION_DECK,0,1,nil)
		and Duel.IsExistingMatchingCard(s.thfilter2,tp,LOCATION_GRAVE,0,1,e:GetHandler()) end
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,nil,2,tp,LOCATION_DECK|LOCATION_GRAVE)
	Duel.SetOperationInfo(0,CATEGORY_LEAVE_GRAVE,nil,1,tp,LOCATION_GRAVE)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
	local g1=Duel.SelectMatchingCard(tp,s.thfilter1,tp,LOCATION_DECK,0,1,1,nil)
	if #g1>0 then
		Duel.SendtoHand(g1,nil,REASON_EFFECT)
		Duel.ConfirmCards(1-tp,g1)
		Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
		local g2=Duel.SelectMatchingCard(tp,s.thfilter2,tp,LOCATION_GRAVE,0,1,1,e:GetHandler())
		if #g2>0 then
			Duel.HintSelection(g2)
			Duel.SendtoHand(g2,nil,REASON_EFFECT)
		end
	end
end