  We present the discovery of a new highly compact quadruple star system, TIC
219006972, consisting of two eclipsing binary stars with orbital periods of 8.3
days and 13.7 days, and an outer orbital period of only 168 days. This period
is a full factor of 2 shorter than the quadruple with the shortest outer period
reported previously, VW LMi, where the two binary components orbit each other
every 355 days. The target was observed by TESS in Full-Frame Images in sectors
14-16, 21-23, 41, 48 and 49, and produced two sets of primary and secondary
eclipses. These show strongly non-linear eclipse timing variations (ETVs) with
an amplitude of $\sim$0.1 days, where the ETVs of the primary and secondary
eclipses, and of the two binaries are all largely positively correlated. This
highlights the strong dynamical interactions between the two binaries and
confirms the compact quadruple configuration of TIC 219006972. The two
eclipsing binaries are nearly circular whereas the quadruple system has an
outer eccentricity of about 0.25. The entire system is nearly edge-on, with a
mutual orbital inclination between the two eclipsing binary star systems of
about 1 degree.
