Most of us use tape measures as an extended ruler for large or difficult-to-reach things.
That’s absolutely what they’re made for, but you may have also noticed tiny black diamonds or red boxes on the handy tools. To most people, these make no sense at all. So, what are they for? As it turns out, they’re incredibly useful for carpenters and construction workers, and it all comes down to math.
These symbols precisely mark standard distances that anyone building a house should know. In the video below, carpenter Tom Hintz explains further.