In this optical illusion you will see gray dots at the intersections in the grid below. This is known as the Hermann-grid illusion. Those gray dots aren't really there. You can make them disappear by looking directly at the intersection.
In this Instructable we will go over a quick method for recreating such a grid and see some variations as well.
Step 1: Starting the grid
Get your favorite graphics program and we'll get started.
Start by making your basic building block: a black square with two identical smaller blue squares attached to the right side and bottom. The blue squares will determine the distance between the black squares.