My sewing machine needed a mat and I wanted to make a tumbler pattern. I didn't have the ruler and no way I could afford one. Made a little research and found the easier way to do it. I Used a card from a charm pack. It's strong and it has the right size
Mark an inch from each top and cut the card
Place the card on top of your fabric square and cut it using your rotary. you can cut two or three squares at a time if you fell comfortable.
They will look like this
Cut as many as you think you'll need and sew them into rows
Join all the finished rows together and you will get this
I quilted mine sewing straight lines in both sides of the seams. you can quilt it the way you prefer
I added another rows and made four little pockets, they're great to keep my cutter, scissors and other stuff
Et....Voilá! My sewing machine has a new tumbler mat. I love it. Next time I think I'll try something bigger.