The objects with the outlined contours is another kind of Line icons. They're known as contour drawings. You can also find another kind of icons: the items are without some strict outlines. They are named gesture drawings. Such drawings are being widely used by skilled artists who can repeat the outlines of the object right after seeing it. It is not a complete piece of art but rather a sketch which demands 20-30 seconds to be drawn.
Another technique is adding some halftones and shades to the object with the help of short lines and crosshatching. Their frequency and pencil pressure can be different. And this variety impart more three-dimensional look to the object. This trick is widely used in world wide web design as well. It helps to make amazing Line icons, logos and buttons.The lines with the dots not combining the singular elements are known as open lines. The lines can be gesture-like, parallel, contour etc. as well. Contour drawing consists of fantastic simplicity and refinement of line design. You may be want to know what is bezier curves in computer graphics? It's such type of the curves that are essential for creating complex line shapes. These curves are handy small features necessary for creating the vector shapes like line icons, unusual buttons etc.Today computer technologies reached such a level when it becomes possible to reproduce exactly the same designs or just build new shapes that based on some older ones. The great thing - it can be done without extra efforts and time. Another benefit is that it is easy to return to the previous adjustments with a help of the history panel. As a result there is no need to design Line web icons from scratch in case you have made some mistakes.