Has it perished? Does it exist?

Yesterday, His Holiness the Dalai Lama finished three days of teachings at Radio City Music Hall, here in New York City. The teachings were on the Diamond Cutter Sutra & Seventy Verses on Emptiness.

To be blunt, the teachings, which I attended, made me aware of how I need to start practicing again and seriously read the sutras. I vascillated between drowsy and awake, aware and asleep, informed and ignorant. This was the second series of His Holiness' teachings that I've attended and the fourth time I've heard him lecture. When His Holiness talks to the general public, it is very easy to follow, but when he gives teachings, it's pretty dense for my level of knowledge.

There hasn't been a lot of philosophy and theory on this blog lately, and there is a connection between His Holiness' lecture and urban exploration. I hope to have some time to reflect upon the Diamond Cutter Sutra during my travels in the next week, and the below is a good start. At the very least, I will think of these verses and reflect upon abandoned sites:

From the Seventy Verses on Emptiness by Nagarjuna (translated into English by Gareth Sparham):

9.
Permanent is not; impermanent is not; a self is not; not a self [is not]; clean is not; not clean is not; happy is not; suffering is not.

21.
A state of existence would be a permanent state, and if it did not exist, it would be thoroughly annihilated. There would be those two [extremes] if there were things. Hence we do not assert things.

31.
It is not [the mark of what] has not perished, nor [of what] has perished. What has lasted is not lasting and what has not lasted does not last either. The produced and unproduced are not produced.

58.
All are impermanent. Alternatively, impermanence and permanence do not exist. Were things [to have an own-being], they would be impermanent or permanent, but how could that be?

Could somebody please write Mahayana Buddhism and the Art of Urban Exploration? I'd really like to read it.