How do you create something that can measure distances by estimating?

Question

how do you create some tool (that hasn't been created before) that can app. measure the space between two distances like two cars or just two pencils like 2ft away from eachother?

not using a tape measure, or foot steps etc

whats a common reflection point?

Answer 1

Hi. Two mirrors with a common reflection point. Measure the angle of the mirrors and triangulate.