I made sure that when I taped the weights to the flap, there were no loose ends to get caught up in the blade. (I'm lazy, but not so lazy that I want...
I don't like mowing my lawn, so I decided if I have to do it, I might as well give myself some enjoyment. I started out with this small project, and figured if my lawn-rolling rig worked, I'd do some cooler patterns next time. One of the reasons the "roller" is so rigged is because I was too lazy to actually make one out of PVC and lead shot, which was my original plan. Now that I know this technique works, I'll probably make one like I had planned. Duct tape tends to come off too easy, but it's also easy to rig things up with it. Have fun with this, and if you can figure out some cool patterns, let me know!
When striping your lawn, the weight of the roller pushes the grass in one direction or the other. Because the blades are leaning opposite directions when you finish, the light reflects off of them differently, hence giving the appearance of stripes. Just like when you vacuum your carpet. Now, I didn't make a roller, for reasons aforementioned, but I decided to just take some weights, and duct tape them to the flap on the back of my lawnmower. If I wasn't so lazy, I would have experimented with different weights, and see how that affected the stripes, or how hard it was to push the mower, but I am, so I just went with what I had laying around.
Step 2: Attach weight
I made sure that when I taped the weights to the flap, there were no loose ends to get caught up in the blade. (I'm lazy, but not so lazy that I want to see what happens when cast iron meets whirling steel!) I also checked to see if the weights stretched the flap out, making it able to get caught in the blades. In both cases, I was safe. In my next revision, the roller I build will attach to the mower, and roll a few inches behind the flap. Once I was taped up and safe, I got to mowing! The weight will now bend your grass in the direction you mow, giving it that professional "I'm so important that I have to hire a landscaping crew because my time is far to precious to work on the lawn" look. Have fun, and let me know if you come up with some cool designs. I read somewhere that one guy mows it in a diamond pattern, but changes the length for the crosscuts, giving him a 3-d look to his lawn. If anyone does this, please send me some photos!