Legal Disclaimer: I do not own, work for, or gain profit from, any actions taken henceforth in my worldly existence, including this collection of crap on eva. dont blame me, it was a hardware problem

The main principle behind the EVA project is that of effective defense. In order to defend one's self from an attacker, one must understand this attacker, and equip one's self with the aparatus needed to match or overthrow the aggressor. Since the inhabbitants of Tokyo 3 faced an other-worldly threat, they required an other-worldly weapon with which to defend themselves. Let us now examine this weapon.

The basic evangelion unit zero consists of a physical structure as well as an abstract, psychological aspect, which provided much of the mystery to the ignorant parties surrounding it.

Physical Structure
Approx. 25m in height, 100 tonnes in g=1 weight, the Eva 0 is a formidable match on the battlefield. It is a bioengineered mass of muscle tissue and titanium/plymer alloys. The entry plug is coated along its outer edge with highly sensitive solder pad contacts, which coduct the exact open circuit into the plug as required, and then lead to the main LCL conductors.
Apart from oxygenating the blood, the LCL serves as the eva's main nerve link to the pilot. Rhybosomal carrier protiens, designed using the most state of the art nanaoprocessors and microscopic engineering, carry the signal, in the form of chemical compound codes, to the plugs Chem Encoder module. Each compound delivered by the rhybosomal carrier system is specially designed to return a value in binary form, based on the chemical's molecular makeup. This makeup results in a code that specifies where it came from, its main signal, and what is to be done with it. Once in the Chem Encoder, the encoder sends out the binary signal across the specified solder pad to the eva structure main. the signal travels to the CPU system, where the appropriate mechanical actions are performed, such as moving a limb or firing a weapon. the external to internal nerve synchronization works in much the same way. a speciallized subunit of the eva's cpu structure constantly monitors the eva's external and internal integrity. if this integrity is breached, an electronic pulse is send from the damaged area to the solder contacts on the entry plug, and from there, the Chem Encoder creates a pathenogenic chemical compound to send to the affected relative area of the pilot, stimulating the pilot's pain receptors. thus, the nerve connection circuits are bidirectional.

the uh, Un-physical, or mental, structure
the basic theory behind the eva/angel relationship is of a reciprocality neutralization statement:

(x/y)(y/x)=1

evas and angels contrast eachother in much the same way
angels are the creations of god, made in the form of man
evas are mans creation, made in the form of god
therefore, the two are meant to cancel each other out, and return peace (represented by 1) to the earth.
This theory seems sound, unless it is examined further. The evas cannot be created in the image of god, following most accepted doctrines, because god cannot be fully understood by the mortal man, and so nothing can be created in his image. And since nerv was fighting angels and adam and lilith, and not shiva and the many limbs of vishnu, we can safely assume the basis of the Evangelion existence to be a christian creation. So, since eva is not an image of god, it is an image of one of god's creations, most likely the angels themselves; those the eva is to do battle with. Therefore, the fomula must be modified. If we let the angels, or their patter at least, the pattern of god's creation in the form of a man, be x, and the creations of man, their weapons and tech and such, be y, the evas can be described as xy. A fusion of sorts. If the angels are the power of god, z, fused with the image of themselves, in the form of man, which has already been defined as x, the angels are xz. Therefore, when the eva and angels meet, the following occurs.

(xy)(xz)=x^2 + xz +xy +zy

Examining this formula, we can simplify it to x^2+zx+xy, since the zy can be eliminated, as the creations of man and god cancel each other out, resulting in peace, 1. Also, as proven, the exchange of angels and evas results in peace. So, (xy)(xz)=1. Therefore, using the law of trasition, x^2+xz+xy=0. Now, following this through, x, the creation of god in the form of man, equals -z-y, that is the opposite of the power of god minus the opposite of the power of man. Now, if the opposing force of god is evil, then -z is this. And, the opposite of the power of man, a finite power, is an infinite power, the power of god. Now, this is where things get a little weird. In order to solve for the angels variable, we need to define at least one of these terms. How do you define evil? Other than -z, the devil is an option, but let us leave that alone for now. The power of god can be defined as ~y, where ~ is infinity. Now, if the power of evil is the opposite of the power of god, and the power of god is the opposite of the power of man, then evil = -~y. Therefore, the fusion of evil and good is y-y, or 0.
What is 0, you ask? Well, it certainly is not peace. Since peace is desired, and eventually obtained, it needs to be defined, to have a measurable value, which 0 does not. Also, peace has been previously defined as 1. So, 0 must be neutrality. Zero is neither positive or negative; good nor evil. So, x, the creation of a god in the image of a man, is neutral, a seemingly astute conclusion, seeing as man is a flawed creature, perverting the immaculate.

Now, refreshing the basic formula, we get:
0=0
Pretty freking simple, if you ask me. Neutrality is neutral, so shit. However, when were the evas ever truly neutral. They were manipulated by the hand of Nerv, so as to be a weapon for man, which was there purpose from the beginning. So, x is a variable, still 0, but different values for the power of good and evil must be subbed in to allow the actions of the evas to be neutral, and the fusion of eva and angel be 1. Again, we must assume some principles and a little wierdness to continue.

Let the world be a triangle. The angles, X,Y,Z are the percent makeups of the different moral powers in the total of the world. If neutrality is half of the world, 90 degrees, then the remaining 90 degrees is divided between god and man. What is the percentage? If the power of man = sin-1(god/h), where h is the hypotenuse of the world. Now, what is the hypotenuse of the world? Since it is the side opposite neutrality, and the largest side in the triangle, let's let it be neutral as well, giving no side any significant overpower right yet. But, since neutrality is 0, the hypotenuse has no length, and the world is undefined by division of 0 (god/0). Is the world undefined? Touch your arm. Feel the pulse or the skin? The world is definitely freakin' defined. Because of this, the hypotenuse cannot be neutral, one side, man or god, has control by opposite angles. If we assume that neutrality still has the right angle in the triangle, then there is still a flaw in the definition of the world. Perhaps, we can inquire, the world is not undefined, just unreal. That is a distinct possibility, since things are not always as they seem, and everything has an unperceived element to it. So, the world can be defined as z*I, where I is the square root of -1. So, man, or evil, is its opposite divided by zI. However, man and evil have been defined in terms of y already. Man is y, and god is ~y. So, man is (~y)/zI. God, alternately, is y/zI. Focusing on man's definition, infinity divided by any finite number is still infinite. But, is I infinite? A good question, with not such a good answer. Because of this, we will ignore it for now. Let's simplify the numerator first. Because infinity is infinite, multiplying it by anything is useless, because how in the heck do you make infinity larger. Therefore, we can ignore the y in the equation, and make ~/zI. Since the division of infinity by a non-real number is, as far as I know, impossible, there would appear to be a flaw in my logic somewhere. And, because it is late, I have no desire to try to find it right now.

Anyhow, the eva's are neutral, except when manipulated by nerv. They could be perhaps the fourth side of the triangle, or neutrality's bisector. Good and evil are , who the hell knows, and the nature of the universe is, oh, lets say 72.