An Optical Illusion On The Wall

Introduction

This is a very short post because I intended to walk the Berwick Walls to the round tower in the main picture, and I got there, walked around it, took some pictures, and then made my way back.

The Tower On The Wall

On my walk there, I had an oat milk latte and some Key Lime Pie at Lowry's. I then passed a number of impressive dwellings until I hit the tower.

The point of this post is: how can a tower seemingly change its construction? I photographed it as a round tower with a level wall yesterday; today it is rectangular with a sloping wall.

I have tried looking from a number of angles, but from the other side of the Tweed, it is definitely rectangular.

Conclusion.

I would love to know if there is any explanation, and if you know, let me know in the comments. The nearest thing to this is the Sydney Opera House effect:

The music is "Just An Illusion" by Imagination.

Thank you so much for reading.

After closer examination, I realise that it is the light that gave me the impression of the tower being round one day and square today. In the first picture, the deep shadow takes your eye away from the side wall, making you focus on th efrontal curve.