dash-dash-dash-dash chalkline

Chalklines are simple devices that leave a continuous straight line along any hard surface.

They do this by passing a length of string through a reservoir of chalk dust which is absorbed into the fabric of the string. This is then transferred to the surface when the stretched string is pulled back and releasee against it. (see video link if you're not sure what this looks like in action)

"dash-dash-dash-dash" chalkline works in exactly the same way, except it can leave evenly spaced dashes instead of a solid line.

It can do this because the string itself only absorbs the chalk dust at periodic intervals (the dashes) with the blank no chalk spaces formed by sections having been impregnated with Teflon or some other type of flexible coating that acts as a chalk dust barrier.

Now when you want to mark the length of a wall to receive a line of holes drilled at regular pre marked intervals, (for example) you simply drop in the cartridge (another innovation) with the required measurement dash spacing and twang the line in place.