As Ifletcher said -- except they don't have to be curved rulers --- straight edge rulers make crosshatching, curved rulers make curved crosshatching. I, too, believe you'd just want to do the block -- and not a whole quilt. As for size of ruler, most machines wouldn't let you do a "whole" quilt as one big crosshatching anyway, I do crosshatching using a 6" ruler!!! You just have to not daydream and run off the edge of the ruler (yeah, right LOL)