math.randomseed(os.time())
function test_update(i, x, y, s, n)
randx=math.random(4,607)
randy=math.random(4,379)
if tpt.get_property("type",randx,randy) == 0 then
tpt.delete(i)
tpt.create(randx,randy,"plsm")
end
end
tpt.element_func(test_update, tpt.el.plsm.id)