To use this protractor, start by placing the bottom on the underside of a piece of paper. The pegs on the base plate will stick up through the paper, and the top can then be fitted over those pegs. Now, simply snap the pointer into place, and away you go! The pointer has marks in it that allow the user to measure angles with more precision, and holes in the protractor allow the drawing of lines and arcs. Next, set the pointer to the desired angle. The pointer fits between the 5 and 10 degree markings to act as a useful guide. The 5 degree markings are inset so you can easily feel between adjacent angle markings such as 15 and 20 degrees. The holes for the stylus are in the center of the marks. Note that the 0, 45, 90, 135, and 180 degree marks are extended so they can be easily located. Mark the angle on the inside area of the protractor (there are five additional locations along the pointer) and on the outer edge where the gnomon is near the angle marks. The angle has now been marked and when the protractor is removed, the paper retains the indented markings. Turn the paper over and the tactile angle is easily felt. A tactile 180 degree semi-circle with marks every 5 degrees and additional marks at 0, 45, 90, 135, and 180 degrees can easily be constructed with this protractor. The base is marked with rulings spaced 1 cm apart with an extra mark at the circle's center.