Holding small objects is a benefit of good fine motor skills, and to work on developing and perfecting those fine motor skills, you can use small objects as a tool. Push pins or thumb tacks that you would use in a cork board are usually a perfect size to facilitate a good tripod grasp. The pins are too small to use a gross grasp on, so they facilitate a good tripod or 3-jaw chuck grasp. Poking the pins around a picture makes a nice picture, and it is even better when you have the picture that you are poking, and a blank piece of paper underneath so that you can see the finished product with just the holes without the dots.
You first have to have a squishy surface that you put the paper on, which can be a cork board, fun foam, carpet, etc. You can modify the difficulty of poking by having the picture printed on regular paper or on cardstock, and you can change the position used by taping it up on a wall, lay on the floor, use a slant board, or even tape them to the bottom of the table so that the kids have to poke up to the table.
You also want to make sure that the kids do have a good grip on the push pin. There are some neat Jumbo push pins that may be good for kids with a really weak grasp, and the small push pins can fit inside a pencil grip to help work on that grasp. I only had some little round push pins, which I put inside a basic pencil top eraser. The eraser is the perfect shape for a tripod grasp.
I love this set of poke pictures because they are not too big and they have the dots at the perfect distance apart. They are made by the same therapist who created the original Pencil Obstacle Courses. Included are 21 different pictures as well as upper and lower case alphabet and numbers. You can also find them on Therapy Fun Store.