4. With the pattern still folded in half lengthwise (figure C) and, using a ruler, draw a line from the horizontal crease straight down to the bottom of the tree and 1/8 inch away from the fold (figure D). Using a craft knife and ruler, cut out along this line. When the pattern is opened you should have a 1/4-inch opening down the center (figure E). 5. Place pattern on one of the foam trees, trace around the center opening slit, remove pattern then cut out the slit using a ruler and sharp craft knife. Before you cut the entire slit, check to be certain that it is wide enough to fit over another piece of foam.
6. You will now need to cut a similar slit in the other tree but this one will need to go from the center crease to the top of the tree. You can use the original pattern and simply place it upside down or, if this is too tricky, cut another paper pattern and cut the center slit from the center crease up to the top.
7. When both trees are cut, put them together to make certain that they fit perfectly and that the tree sits flat on the table. If it is necessary to make any adjustments in the center slit, now is the time to do it.