Bhagavad Gita Verse 16, Chapter 15

dvaamimau purushau loke ksharaakshara eva cha |
ksharaha sarvaani bhootaani kootasthokshara uchhyate || 16 ||
 
There are two beings in this world, the perishable and the imperishable. All beings constitute the perishable, the Kootastha is called the imperishable.
 
dvaau : two
imau : these
purushau : beings
loke : in this world
ksharaha : perishable
aksharaha : imperishable
eva : also
cha : and
ksharaha : imperishable
sarvaani : all
bhootaani : beings
kootasthaha : Kootastha
kshara : perishable
uchhyate : is called
 
Computer programmers love to create video games that can put the player in a gigantic virtual world where they can blow up aliens. What is interesting is that the same computer game can create a different world each time, with different kinds of aliens in different place. In other words, the infinitely complex virtual worlds created by the game can change, but the computer game program remains the same. Our visible universe is quite similar.
 
Shri Krishna begins to summarize the teaching of this chapter by asserting that everything in the world can be classified into two category. The first category comprises the visible world, the tangible world which comprises all living and inert beings. The second category comprises the invisible entity called Maaya. Maaya is like the computer game program that is invisible, yet has the power to create infinitely complex universes over and over again. The first category is termed kshara or perishable, because the universe has a beginning and end. The second category is termed akshara or imperishable, because it outlives the perishable.
 
So therefore, let's examine this teaching from two standpoints. From our standpoint, the standpoint of the "I" - the kshara, the perishable is our physical body. The akshara, the imperishable is the jeeva, as defined in the previous shlokas. From the standpoint of the world, the standpoint of the "that" - the kshara is the visible universe. The akshara refers to Maaya, the seed of infinite universes, present, past and future.
 
Let’s now look at some of the terms used in the shloka. Koota means illusion, and therefore kootastha means that which can create several illusions. Another clarification is around the imperishability of Maaya. If Maaya is imperishable, how can we get out of it? The answer is that Maaya is imperishable till we realize our true nature and attain liberation. Each category is called a Purusha or a being because both of them are limitations or upaadhis of Ishvara, as we shall see in the next shloka.