In the 1600s there was developed a stylus that could draw a line with a specific width called a ruling pen. The stylus had two curved metal pieces, which were joined by a screw. Ink was trickled between the blades, from which it flowed evenly across the paper. The basic model was maintained for a long time, with minor modifications, until the 1930s when the German technical drawing pens came to the market. A ruling pen of 1901 is shown here.