Grünbaum–Rigby configuration
... that although the Grünbaum–Rigby configuration has been studied since 1879, it was not depicted in its realization as three overlaid heptagrams until 1990?
... that although the <b id="mwAj4"><a href="./Grünbaum–Rigby_configuration" id="mwAj8" rel="mw:WikiLink" title="Grünbaum–Rigby configuration">Grünbaum–Rigby configuration</a></b> <i id="mwAkA">(pictured)</i> has been studied since 1879, it was not depicted in its realization as three overlaid <a href="./Heptagram" id="mwAkE" rel="mw:WikiLink" title="Heptagram">heptagrams</a> until 1990?