  We present a comprehensive analysis of the formation and evolution of a
fan-spine-like configuration that developed over a complex photospheric
configuration where dispersed negative polarity regions were surrounded by
positive polarity regions. This unique photospheric configuration, analogous to
the geological "atoll" shape, hosted four homologous flares within its
boundary. Computation of the degree of squashing factor (Q) maps clearly
revealed an elongated region of high Q-values between the inner and outer
spine-like lines, implying the presence of an hyperbolic flux tube (HFT). The
coronal region associated with the photospheric atoll configuration was
distinctly identified in the form of a diffused dome-shaped bright structure
directly observed in EUV images. A filament channel resided near the boundary
of the atoll region. The activation and eruption of flux ropes from the
filament channel led to the onset of four eruptive homologous quasi-circular
ribbon flares within an interval of $\approx$11 hours. During the interval of
the four flares, we observed continuous decay and cancellation of negative
polarity flux within the atoll region. Accordingly, the apparent length of the
HFT gradually reduced to a null-point-like configuration before the fourth
flare. Prior to each flare, we observed localised brightening beneath the
filaments which, together with flux cancellation, provided support for the
tether-cutting model of solar eruption. The analysis of magnetic decay index
revealed favourable conditions for the eruption, once the pre-activated flux
ropes attained the critical heights for torus instability.
