maths · projective geometry

Two poles of one sphere

The Śrī Yantra turned inside out by circle inversion, then wrapped onto a ball by stereographic projection. On the sphere the inversion is just a flip, and the bindu and infinity are the two poles.

Explore it

Spin the yantra and its inversion on the Riemann sphere, with the plane underneath. Slide the lift, compare stereographic with great circles, switch the sphere off to see just the plane, and add or remove the outer yantra (lotus rings and bhupura).

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Overlays

The yantra laid over its own inversions: one in the outer rim, one in a smaller circle tuned so the trefoil's lobe meetings land on the outer triangle's midpoints. Toggle any of the three.

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four upward triangles · five downward · the bindu

Triangle coordinates follow a numerical solution of the yantra's concurrency conditions (after Kulaichev and Huet), drawn as 27 lines with 29 triple points.