The Klein bottle is a non-orientable closed surface with no boundary — it has no inside or outside. It cannot be embedded in ℝ³ without self-intersection. This shows the Figure-8 / Lawson parametrization. Drag to rotate.
Parametrization
χ(Klein bottle) = 0
2 Möbius bands glued
Non-orientable: yes
Self-intersects in ℝ³
Embeds in ℝ⁴ cleanly
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