  Following the work of Gangl, Goncharov and Levin in [GGL], we will give a
combinatorial framework for motivic study of iterated integrals on the affine
line. We will show that under a certain genericity condition these
combinatorial objects yield to elements in the motivic Hopf algebra constructed
in Bloch-Kriz [BK]. It will be shown that the Hodge realization of these
elements coincides with the Hodge structure induced from the fundamental torsor
of path of punctured affine line.
