geisha_red_black

Equation

\[ x^2yz+x^2z^2 = y^3z+y^3 \]

Properties:

  • degree 4
  • two singular curves, both lines. one is a cusp, the other is a self-crossing. at least in terms of the real part...
  • two singular points, one at the intersection of the two singular lines -- at the origin. the other is at \( (0,0,-1) \), and is a cusp singularity, lying only on the singular \(z\)-axis
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geisha_in_progress

Some story

The support came off quite nicely, except where the two separate bodies join, at \( (0,0,-1) \), where the printed surface broke. Not surprising. PLA is a brittle plastic, so even a little extra force while removing support is likely to break these point singularities. So I hot-glued it back together.

Sphere of radius 5, random projection.

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geisha_matlab_points

input