If 2d is only length and width, but not depth then can something really exist in 2d? 2d is length and width, not depth. So if I have an object in 2d (0 depth), then it would be non-existent, right? Paper, graphite, etc. have depth even if it is extremely small. Here is my own theory on the 2cnd dimension:The first thing that comes to my mind would be light, but it is made up of waves which have length width and depth. But I thought for a while and realized that color has no depth, but physically exist in our world. Color being how much light is reflected from an object (or how much of one or more types of light waves are absorbed by an object) then, is 2d. So another question I have is, would 2d be measured by length and width, or something like temperature and frequency?
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I would ask anybody leaving comments to bear in mind that the OP is a potential physicist, at some time in the future and would probably appreciate encouragement. Thanks........ Count_to_10

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 A: 
(...)
  'I do not mean to ask you to accept anything without reasonable ground for
  it. You will soon admit as much as I need from you. You know of course that a
  mathematical line, a line of thickness nil, has no real existence. They taught you that? Neither has a mathematical plane. These things are mere abstractions.'
  'That is all right,' said the Psychologist.
  'Nor, having only length, breadth, and thickness, can a cube have a real
  existence.'
  'There I object,' said Filby. 'Of course a solid body may exist. All real
  things-'
  'So most people think. But wait a moment. Can an
  instantaneous cube exist?'
  'Don't follow you,' said Filby.
  'Can a cube that does not last for any time at all, have a real existence?'
  Filby became pensive. 'Clearly,' the Time Traveller proceeded, 'any real
  body must have extension in four directions: it must have Length, Breadth,
  Thickness, and - Duration. '
  (...)

H. G. Wells, The Time Machine (1895)
A: When you actually research if there are such things as 2D objects, you find that there are many objects that are accepted to be 2D, such as electron gas clouds used in electronics. On the other hand, the orientation of a 2D object is not permanently defined.This means that you would be able to render an object invisible simply by changing the direction of observation. As this is not possible(even these electron clouds could be observed from all angles, even more so with proper equipment), there is, in my opinion, no such thing as a 2D object that has been discovered as of yet.
