The best plan is to draw the box top full size and then carefully work up the design.
Now find a thin, flat piece of board—a box top or a shingle will do—and nail it like a table top on to the top of the post.
Jed took a nail from the half dozen held between his lips and applied its point to the box top.
“Look out for ‘emence numbers of Deer on the banks,’ now,” sung out John, who had the Journal on a box top near by.
He crawled around on his box top and then managed to clamber up on the slanting board, one edge of which rested on the box.
Screw battens across, and screw the whole firmly to the box top from the inside.