While you are always more then welcome to use whatever colors you want for any piece you crochet, for the best illusion effect it is recommended to use 4-5 colors. Black being used through out the whole piece and then shades of another color starting with the lightest shade on the outside of the hole and working toward the darkest shade in the center to create the illusion of depth within the hole. We have a Black and White (shades of grey) version here if you would like to look to it as an example and see what colors are uses in the description. >> https://www.hookedcreation.com/Theres-a-Hole-In-My-Bed-TSS-Tunisian-Simple-Stitch-Left-Handed-Throw-Blanket-Graphghan-Crochet-Pattern--PDF-Download_p_4236.html