The objects with the outlined contours is another kind of Line icons. They are known as contour drawings. There are items without some strict outlines that are rather some hint than actual contour of line icons. They're referred to as gesture drawings. Skilled designers often use such kind of drawings because they are able to repeat the outlines of the object right after seeing it.
One more technique is adding some halftones and shades to the object. You can do it with the help of short lines and crosshatching. Do not afraid to alter their frequency and pencil pressure. Such variety creates more three-dimensional look to the object. This trick is widely used in web design as well. So this technique is definitely helping in creation of amazing Line web icons, logos and buttons.Furthermore lets get information on open lines. It is such type of the lines where the dots not combining the singular elements. The lines can as well be parallel, gesture-like, contour and so on. Contour drawing includes superb simplicity and refinement of line design. You may be wonder what's bezier curves in computer graphics? It's such kind of the curves which are necessary for creating complex line shapes. These curves are real helpers in creation of the vector shapes such as line icons, unusual buttons etc. Nowadays computer technologies reached such a level when it becomes possible to reproduce the same designs or even build new shapes that based on some older ones. The great thing - it can be done without extra efforts and time. Furthermore, it is possible to go back to the previous adjustments due to the history panel. So you do not have to design Line icons from scratch after you've made some mistakes.