function Check_Amount(Arg,Parent)
local Arg2 = {}
for __,v in pairs(Parent:GetChildren())do
if(v.Name == Arg)then
table.insert(Arg2,v)
end
end
return Arg2
end

while true do
    if(#Check_Amount("Stone",script.Parent) < 8)then
        wait()
        local Rock = Instance.new("Part", script.Parent)
        Rock.Name="Stone"
        Rock.Size = Vector3.new(2, 1.2, 2)
        Rock.Position = Vector3.new(math.random(script.Parent.Position.X-12,script.Parent.Position.X+12),1.7,math.random(script.Parent.Position.Z-12,script.Parent.Position.Z+12))
        wait(5)
    else
        break
    end
end