Canonical flowchart symbols  : The graphical aide called a flowchart offers a way to describe and document an algorithm (and a computer program of one). Like program flow of a Minsky machine, a flowchart always starts at the top of a page and proceeds down. Its primary symbols are only four: the directed arrow showing program flow, the rectangle (SEQUENCE, GOTO), the diamond (IF-THEN-ELSE), and the dot (OR-tie). The Böhm–Jacopini canonical structures are made of these primitive shapes. Sub-structures can "nest" in rectangles, but only if a single exit occurs from the superstructure. The symbols, and their use to build the canonical structures, are shown in the diagram.
Briefly state your position, state why the problem you are working on is important, and indicate the important questions that need to be answered; this is your "Introduction." Push quickly through this draft--don't worry about spelling, don't search for exactly the right word, don't hassle yourself with grammar, don't worry overmuch about sequence--that's why this is called a "rough draft." Deal with these during your revisions. The point of a rough draft is to get your ideas on paper. Once they are there, you can deal with the superficial (though very important) problems.