  We use the two-components bipolar toy model of core collapse supernova (CCSN)
ejecta to fit the rapid decline from maximum luminosity in the light curve of
the type IIb CCSN SN 2018gk (ASASSN-18am). In this toy model we use a template
light curve from a different CCSN that is similar to SN 2018gk, but that has no
rapid drop in its light curve. The bipolar morphology that we model with a
polar ejecta and an equatorial ejecta increases the maximum luminosity and
causes a steeper decline for an equatorial observer, relative to a similar
spherical explosion. The total energy and mass of our toy model for SN 2018gk
are E=5e51 erg and M=2.7Mo. This explosion energy is more than what a
neutrino-driven explosion mechanism can supply, implying that jets exploded SN
2018gk. These energetic jets likely shaped the ejecta to a bipolar morphology,
as our toy model requires. We crudely estimate that f=2-5% of all CCSNe show
this behavior, most being hydrogen deficient (stripped-envelope) CCSNe, as we
observe them from the equatorial plane. We estimate the overall fraction of
CCSNe that have a pronounced bipolar morphology to be 5-15% of all CCSNe.
