Thanks everyone, some great suggestions here. And thanks for the pic Hillcountrygal, it helps to actually see how the straight lines look on the snowballs. I might try a combination of a grid but using the wavy line stitch on my machine. I have a walking foot, with a thing you fix to the side so you can measure accurately, but can only use the walking foot for straight stitch or zigzag. If I don't use the walking foot I have terrible problems getting the correct tension to avoid puckering, so lots of options to weigh up! Will try to remember to post a pic when it is finished!