How to draw a standard scale

For a standard scale line, first draw two vertical straight lines, then draw a rounded corner with a protractor, and then draw a positive angle line of 45 degrees from the right angle. This included angle is the standard scale line.

Ghost table is an astronomical instrument for measuring the length of the sun shadow, which consists of two parts: ghost table and ghost table. Like the sundial, the sundial is an ancient astronomical instrument, which uses the shadow of the sun to measure. The so-called altimeter method, popularly speaking, is to erect a pole perpendicular to the ground and determine the seasonal change by observing and recording the change of its shadow at noon. A straight rod perpendicular to the ground is called a "table", and a scale horizontally placed on the ground and engraved with scales to measure the shadow length is called a "GUI".