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  • A transparent model of Cayley's cubic surface, with the 27 real lines marked on them. I've only seen plaster models of this. (Actually, I want this for my birthday. Ahem...)

  • A transparent plastic cone and a laser light to cut it into conics and, more fun, similarly transparent models of quadrics and lights to check the theorem that the shadow lines on cuadrics are plane curves.
show/hide this revision's text 1 [made Community Wiki]

  • A transparent model of Cayley's cubic surface, with the 27 real lines marked on them. I've only seen plaster models of this.

  • A transparent plastic cone and a laser light to cut it into conics and, more fun, similarly transparent models of quadrics and lights to check the theorem that the shadow lines on cuadrics are plane curves.