Ever try to carefully mark a line around four faces of a workpiece and not have the last line meet up with the first? Here's a foolproof way to get it perfect: Score the top face on your cut line with a square and a marking knife. Now place the marking knife blade in the score at one edge of the workpiece, as shown; slide your square up to it; and score the second face. Repeat the process for the opposite end of the first cut and again to connect the scores on the bottom of the workpiece.