How do I make a tool regenerate after a robloxian has taken it?

How do I make a tool regenerate after a robloxian has taken it, and that robloxian can't take it again?!

local clone = script.Parent.Torch:Clone(999999999999999999)
while true do wait(120)
    local g = script.Parent:findFirstChild("School Book")
    if g ~= nil then

    else
        local o = clone:Clone()
        o.Parent = script.Parent
        o:MakeJoints()
    end
end