Composition question

I like the picture, and it took me a little while to find some of the reasons, although I cannot reach any conclusion. But I think what is pleasant is that it leaves you a sort of a doubt somewhere. Intriguing, but I do not know how to express it better !

• There is no particular subject, everything is a subject. The picture could be fragmented in smaller pictures, each with a subject. A sort of a mosaic
  
• The shadows give a very linear/architectural aspect to the picture
• There are 2 strong diagonal lines that break the shadow grid pattern (the hand rail is luckily extended left and right, then the strong shadow line cutting it at the top left)
  

Overall, the picture looks more like a drawing than a photography, although it is a photography. It is almost unrealistic...

Sorry I cannot explain myself better, but congratulations on this nicely, although strangely balanced picture !

Marc