When preparing to build a foundation or building, begin by staking out one side, like the upright side of the letter 'L'. Measure out 6 feet from the corner and lay a stick across the line. Then run your next string from the same corner (like the other side of the letter 'L') and lay a stick across the line 8 feet from the corner. If the 'L' is square the diagonal distance between the two marked points (the 6 and the 8)will be 10 feet. If not, move one string or the other until square. For smaller buildings use 3,4 and 5 feet.
FYI, this was known as the 47th Problem of Euclid and was solved by Pythagoras a long ole time ago. Nowadays, we just call it the rule of 6,8 and 10. So's ya know!
Kent Hartland, MO, entered 2006-10-17