  In this note we connect the language of Bessis's Garisde categories with
Salvetti's metrical-hemisphere complexes in order to find new examples of weak
Garside groups. As our main example, we show that the fundamental group of the
(appropriately defined) complexified complement of a pseudohyperplane
arrangement is a weak Garside group. As a consequence of the Folkman-Lawrence
topological realization theorem, we also show that fundamental group of the
Salvetti complex of a ("simplicial") oriented matroid is a weak Garside group.
This provides novel examples of weak Garside groups.
