Square and circle in isolation look just like what they exactly are.
A square will look like a square.
A circle will look like a circle.
But if they are combined, or superimposed onto each other, different visual appearances happen.
One example is shown below.
What is interesting is that the circles look a bit of odd and distorted.
This is the eye and brain communication part at play.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj46vlL1Jh5co5xPeU6JKtX51fgK6c2ha3LZup2g6lN9MPeWb_8_SD5Axc_qlQN0rB9R0FTr-XLA7V8aVj0eWTAgOrgv9pv5t9OsaObjoOdlUWXaKtBxwePoLZXaTxyJ6vqapyv33tQ_Sc/s400/Square_Circle.gif)
:D