  For the case of two light flavors we propose the stringy description of the
system consisting of two heavy and three light quarks, with the aim of
exploring the quark organization inside the system and its low-lying
Born-Oppenheimer potentials as a function of the heavy quark separation. Our
analysis reveals several critical separations related to the processes of
string reconnection, breaking and junction annihilation. We find that a compact
pentaquark configuration makes the dominant contribution to the potential of
the first excited state at small separations, and for separations larger than
$0.1\,\text{fm}$, the antiquark-diquark-diquark structure emerges. Moreover, it
turns out that the length scale of string junction annihilation is the same as
that for the $QQ\bar q\bar q$ system. We also discuss the relation to the
potential of the $QQq$ system and some relations among the masses of hadrons in
the heavy quark limit.
