Like walls and fences, it is symbolizing the inaccessibility of something. The repetition of this image points to the inability to move forward on the path undertaken. The area you cannot reach because of the barrier is the higher reality you want to achieve. Something is interfering with your path, preventing you from getting what you really want in life.
Gallery of dreams
Do animals dream?
Research conducted by various scientists show that animals do experience dream while sleeping. They also experience similar sleep stages like human beings - REM and Non-REM. If you have noticed a dog sleep, it might sometimes wag its tail, this indicates some response to its dream. A study was conducted in a cat by removing a part of the brain stem, which will not prevent it from reacting to the dream during REM. It was noted in some cats they were aggressively chasing mice as in reality.
Types of sleep
There are two types of sleep that most of the humans undergo - REM and NREM. REM refers to the Rapid Eye Movement and NREM refers to Non-Rapid Eye Movement. Every individual will alternate these two types of sleep. Non-REM sleep will occur for a short period of time in the first stage of your sleep followed by the REM sleep. Dreams occur during the REM stage, where it lasts for 20 minutes. According to a researcher, J. Allan Hobson, dreams that occur in REM stage are usually forgotten when the individual wakes up. Studies conducted on patients during sleep shows that the frontal lobes in the brain, that are responsible for storing information, are inactive during the REM stage, which is the main cause for forgetting the dreams. Studies also show that this is the stage where you have the most intense dreams.