The Paint-By-Grids Guide Set requires no math, rulers or gridding of canvases, and is designed to work exclusively with our Gridded Canvases. The Guide Set includes 15 image guides for any size picture and a comprehensive 10 page drawing and painting tutorial with helpful tips and tricks on everything from color charts and mixing, brush technique and use, to shapes and values, and of course, the unique Paint-By-Grids gridding features.