Contrast in the park

I wish if you look at first to the video before to read.. guess which is the contrast between the images.

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During my journey in the park I took many pictures, I didn't know which subject I was going to take for my contrast extension workshop..

I liked to looked really deep, every single details of the park, sometimes we are too busy to stop and look rally close of simple things..

then I noticed the circle shape and the straight line where the more common characteristic of my pictures... I compared not only the shape but also the natural shape and the one from the human made..