Can this shape be traced in a single line without lifting my pencil of the paper? Recently, a friend of mine gave me this challenge to trace this object in one line, without lifting a finger of the paper, and without tracing a line more than once, saying it was possible. 
P.S, the curvy squares at the end are actually ment to be semi-circles
Every time I try to do it myself, I always get so close with only one line left. I know this type of problems is generally solved using graph-theory (Not saying that this is necessarily solvable) , so any help is appreciated!

Not possible, by Euler: There are four vertices of odd-degree.  In the best case, you will be missing a line connecting two of the corners.
