Graph paper is one of my essential tools. Whenever I am looking at quilts on the screen or in person I am aware of block construction. Whenever I see one that is unusual and interesting I graph it out. As Jan said you can assign any value you want to each square and create the block in several sizes. Colored pencils help make the block understandable. I keep them in a sketch book. Should I decide to use the block I make a copy, cut it apart and add the seam allowances and use the resulting pieces as templates. Then I look over the pieces to see if I can have a system and rotary cut to save time and fabric. I have saved lots of money by not having to buy a pattern for every square I like.