Cut the top of the post. The top post will be shaped like a pyramid at the top. From the top of the post, measure down 6-inches and make a mark. Make a line around the entire post with your speed square. At the top center of one side of the post, make a mark. With your speed square, make two lines, one from both corners to make a triangle. Following the lines, cut the post with the band saw. Roll the post over to one of the adjacent sides, and mark from the corner of the 6-inch mark up to the center of the top. Cut the post along the lines again.
Make a tongue at the bottom of the post with a wide base that slopes inward as it rises toward the center of the post. On one side of the post, measure up 4 inches from the bottom left corner and make a mark. From that mark, measure across the board 1 1/2 inches and make another mark. Connect the two marks with a line. From the bottom left corner, measure directly across and make a mark at 1-inches. Connect that mark with your 1 1/2-inch mark. Do the same on the right side of the board. You have two opposing trapezoids. Cut them out with your ban saw to create the tongue.
Cut the tops of your four 2 by 2-inch boards at a 6-degree angle with your speed square and band saw. Drill the four legs to the tongue of the top post, two on each side of the tongue, but with only one screw. The legs should splay at the bottom. If not, flip the board over 180 degrees before drilling it to the tongue. Measure the distance between the two legs of one side. Adjust them until they are 22 inches apart, then drill another screw into the tongue through each leg.
Cut the 2 by 4-inch board into 22-inch lengths for spreaders. Cut both ends of each board at a 6-degree angle, so they match the slope of the legs. Cut the left side of each board 6 degrees to the right and the right side 6 degrees to the left. Measure up the legs of the obelisk 10-inches and screw the four spreaders to the four sides.
Measure up one leg 15 inches from the top of a spreader and make a mark. From the same spreader, measure up the opposing leg and make a mark. Measure the distance between the two marks. Cut four 1 1/2 by 1/4-inch pieces of lath at this length. Give the ends of each lath a 6-degree angle. Screw the lath to the legs of the obelisk at the marks. Measure up another 15 inches and repeat the process.