I read in a magazine (and this is how it all started) that one of the simplest illusions in nature that we can all relate to is looking in a clear, still pond. You can see the reflection of the clouds above as clear as if they were right there below you. But with a simple mental adjustment, and perhaps a slight re-focusing of the eyes we can also see the bottom of the pond just as clear, ignoring the reflection.
So this is what I did in a lucid dream:
My Dream Journal. November 25, 2013 wrote:It was a sunny day on a suburban street I didn't recognize. I saw a puddle on the ground that reflected the sky above with clouds. It was crystal clear and reminded me of illusions. I started to feel like if I dove in, I would be in the sky so I did. I dove in head first, arms up, and I was almost in a sky, feeling upside down, which was a strange sensation, and then I felt myself flip back right side up and I was out of the puddle again and back in the exact same place. I tried again, but I was apprehensive this time and when I did I hit the ground and could feel it in my fingers. It wasn't painful though.
If I wasn't over-thinking it, I bet I would have ended up in a sky, floating/flying around and the dream scene would have changed.
I haven't stopped pondering illusions and perspectives in lucid dreams. Why is this in the science section? Because we see illusions all the time when awake too, and are important if one is interested in how our minds work and perceive both reality and dreams.