How many paths are there from $A$ to $B,$ if you travel along the edges (lines)? You can travel along each edge at most once, but you can pass through the same point more than once. (You can pass through $B,$ as long as you end up at the point $B.$) [asy] unitsize(1.5 cm); draw((0,0)--dir(60)--(1,0)); draw((0,0)--(1,0)); draw((0,0)--dir(-60)--(1,0)); label("$A$", (0,0), W); label("$B$", (1,0), E); [/asy]