Well both etching and drawing show a whole picture, use ink, and both are considered sketches. 
These are just some simple similarities. Hope this helps.
        
             
        
        
        
It is zigzag because just because
        
                    
             
        
        
        
Answer: A flat sketch 
Explanation:
Before you can create your tech pack, you have to create something called a flat sketch, which is also known as a technical drawing or informally as a flat. This is because a pattern maker will then go in and use this sketch as a basis to create the pattern.
 
        
             
        
        
        
Il Duomo di Firenze<span>, as it is ordinarily called, was begun in 1296 in the </span>Gothic<span> style with the design of </span>Arnolfo di Cambio<span> and completed structurally in 1436 with the dome engineered by </span>Filippo Brunelleschi<span>.</span>