first, you need black , white and if you want to do it like i did, some neon color nail polish. (and an black art-pencil.)

the fundation is gonna be black.


then you do the small quares, in white (its not a problem if they dont really look like squares yet, you will fix that later,)


then, if you just want them white, i would suggest that you take white nailpolish on top of the white, one more time, because then it will look better.
but if you want any other color, you just take the (in my case pink) color, and do the exact same squares on top of your white squares.
if you dont understand why you have to do it in white first, its because the color would'nt show if you just did it on black right away.

and the last step is to correct the edges of the squares. thats why you need a black art-pencil. just paint along the sides of the square, and since the fundation also is black, you wont see, that it even is corrected.
 see? ;)

thats all you need to do ;)