You will find that when you read it aloud in a go, you will miss the fact that there are two 'The' written in between In and Hand. But you do will realize that if you look closely. The reason is that our brain fails to recognize the double word due to the placement of the words. This is the reason why the Pyramid shape was chose for the illusion.
This illusion is also known as the Sander Parallelogram. You might feel that the left blue line is longer than the right one. Go ahead and measure them with a ruler. Surprised right? They both are of same length. However we perceive the left one longer due to the parallelogram figure.
This illusion works on our size perception. You will be surprised to know that both the orange circles are exactly same in the sizes. But you might think that the right one is bigger right? Why? This is because we are perceiving the sizes in relation with the surrounding circles. Since the left ones are larger, we perceive that the inner orange circle is smaller than the right one.
This is one of the classic illusions that has now been taken up by many architects or designers and are used in many shops' or cafeterias' walls. The disorderly black and white squares are responsible for making us perceive that the lines are bent. However they are not. They are all parallel. If you want a proof, you can try measuring with a ruler.
It is true that your brain is producing the results that are not true. You will find that the black dots keep appearing and disappearing as you move your eyes through the image. However, there are no black dots. It is just a perception of our mind.
It is in and out at the same time. Confused? It is just a matter of perception and the way you would want to look at this image. At the first look, you can find it in or out. But at the second glance, you may find the same or even the opposite. If you concentrate you can find it in and out both. The reason is the 2d image of cube that is drawn in perspective 3D. This is why you tend to see the red dot inside the cube however it is not literally possible as it is just a 2D image.
This is a popular illusion. The angular placement of the two rectangles is the reason behind the illusion. It is just the matter of perception. You can perceive it as pointing towards you or even away from you. If you concentrate a bit, you can find both of the results. Take it as an exercise and try to perceive the both.
In reality, there are no grey dots in the picture. It is a black net over a white background. But our brain is processing information that is not real. This is because of the pattern itself. The white squares in between leads to the illusion of white dots which mixed with black color appears grey.
If you scroll the page up and down, you will find out that there is a distinct square in the middle of the image. Now this square is moving. It is made possible due to the strange alignment of the red, orange and yellow stripe creating a perception in our mind that the square in the center is moving relatively to itself and not in a particular direction only.