**Curves and Surfaces:**

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More about proof and what is possible? what is not?**

**A very old problem: In Euclid's geometry,
there are lines that never meet.... but is this true about Flatland? **

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How can someone in Flatland tell whether 2 lines are parallel? **

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Question:Given a point P and a line l in Euclid's geometry is there
a unique line through P that is parallel to l? **

*Euclid's answer...
YES!
In the projective plane.... Yes- the parallel line meets the line at a point on the horizon.*

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Question:Can that be proven from a list of properties (axioms) about the
plane???
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*Show video:"A
non-euclidean Universe."
*Show orthogonal circles in wingeometry?

**and inversion?
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