tikz-gallery-generator

Custum build of stapix for tikz.pablopie.xyz

git clone: git://git.pablopie.xyz/tikz-gallery-generator
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Commit: 3f20849011b3a75ddc7235738b9555da3f585657
Parent: 600c1da2829a50c5f93f65b993c412a732153a5e
Author: Pablo <pablo-escobar@riseup.net>
Date: Wed, 1 May 2024 16:26:32 +0000

Rewrote all of the text alternatives and captions

Also renamed files to better convey their meaning

Also removed sphere-quotient.tex

Diffstat

9 files changed, 219 insertions, 162 deletions

Status	File Name	N° Changes	Insertions	Deletions
Modified	examples/config.yml	243	165	78
Added	examples/images/geodesic-min.tex	54	54	0
Deleted	examples/images/geodesic.tex	54	0	54
Renamed	examples/images/j-function.jpg -> examples/images/j-function-color.jpg	0	0	0
Renamed	examples/images/j-function.svg -> examples/images/j-function-relief.svg	0	0	0
Renamed	examples/images/complex-lattice.tex -> examples/images/lattice.tex	0	0	0
Renamed	examples/images/smooth-manifold.tex -> examples/images/manifold-charts.tex	0	0	0
Renamed	examples/images/riemannian-metric.tex -> examples/images/sphere-metric-comparison.tex	0	0	0
Deleted	examples/images/sphere-quotient.tex	30	0	30

diff --git a/examples/config.yml b/examples/config.yml
@@ -1,94 +1,137 @@
-# TODO: Differenciate between alt texts and captions
+# TODOO: Reorder the content to group images by theme
+# TODOO: Revise all text alternatives and captions
+# TODOO: Make text alternatives concise
 - path: ./images/26-nodes-diagram.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The 26-nodes diagram
+  alt: A circular, symmetric array of 26 points connected by lines
+  caption: "The 26-nodes diagram: a graph encoding certain relations of the
+    Monster simple group"
 
 - path: ./images/caleb-yau.png
   license: CC-BY-SA-2.5
   author: Lunch
   source: https://commons.wikimedia.org/wiki/File:Calabi-Yau-alternate.png
-  alt: A visual representation of the Calebi-Yau manifold
+  alt: A convoluted self-intersecting surface in pastel shades of pink and blue
+  caption: A visual representation of the Calabi-Yau manifold
 
-- path: ./images/complex-lattice.tex
+- path: ./images/lattice.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: A complex lattice with two linearly independent periods
+  alt: Cyan lines highlight the contours of a lattice on the Cartesian plane.
+    Two blue vectors, each corresponding to one of the periods of the lattice,
+    highlight the bounds of its fundamental domain.
+  caption: A 2-dimensional lattice
 
 - path: ./images/complex-surreal-venn.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This picture represents the relationship between the real,
-    complex and surreal numbers
+  alt: Two circles, the first representing the complex numbers and the second
+    representing the surreal numbers, intersect in the middle of picture. Their
+    intersection is labeled as the set of real numbers.
+  caption: A Venn diagram representation of the relationship between the real,
+    complex and surreal numbers (denoted by "No")
 
 - path: ./images/cube.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: A cube
+  alt: A 3-dimensional cube
 
 - path: ./images/diamond.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: A domond-like shape
+  alt: A diamond-like shape
 
-- path: ./images/dihedral-representation-is-irreducible.tex
+- path: ./images/dihedral-representation.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: An ilustration of the proof that the natural real representation
-    of the Dihidral group is irreducible
+  alt: Two axis labeled "x" and "y" span a plane with a triangle on its center.
+    A curve arrow labeled "sigma" represents the action of rotating the
+    triangle by 60°, while an horizontal two-headed arrow labeled "tau"
+    represents reflecting it through the "y" axis.
+  caption: The action of the Dihedral group in the Cartesian plane
 
-- path: ./images/dihedral-representation.tex
+- path: ./images/dihedral-representation-is-irreducible.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The action of the dihedral group in the real plain
+  alt: Two axis labeled "x" and "y" span the Cartesian plane. A curvy arrow
+    labeled "sigma" joins a point "v" and a point labeled "sigma times v".
+  caption: "An illustration of the proof that the natural representation of the
+    Dihidral group is irreducible: the rotational generator of the Dihidral
+    group rotates any vector v by 60° and hence cannot preserve a line
+    through the origin"
 
 - path: ./images/elliptic-curve-group-structure.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The group structure of the points of an elliptic curve
+  alt: Two axis span a plane containing a curve. Two points on the curve are
+    labeled "P" and "Q", and a violet line passing through them intersects the
+    curve in a third point. A violet vertical line passing through this third
+    point intersects the curve at a fourth point, labeled "P + Q".
+  caption: The geometric group law of an elliptic curve
 
 - path: ./images/euclidian-plane.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The Cartesian plane
+  alt: A tilted rectangle labeled "R²"
+  caption: The Cartesian plane
 
 - path: ./images/finite-topological-plot.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: A plot of the number of topological spaces of n points in
-    logarithmic scale
+  alt: A bar chart with thin blue bars marked by thick circles on their tops.
+    The x-axis is labeled "n" and ranges from 0 to 20. The y-axis is labeled
+    "log(# topological spaces of n points)" and ranges from 0 to a little over
+    80. On the top of the figure a title reads "Finite Topological Spaces".
+  caption: Log of the number of distinct topologies (counting homeomorphic
+    topologies) one can endow a finite set
 
 - path: ./images/galois-lattice-antisomorphism.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The lattice anti-isomorphism between the lattice of the
-    subgroups of the Galois group of a Galois extension and the lattice of
-    intermediary subfields of such extension.
+  alt: The contours of two order-theoretic lattices lie side by side. The
+    lattices are organized in stages, marked by different labels. At each stage
+    the two lattices are connected by a thing dotted horizontal line.
+  caption: The lattice anti-isomorphism between the lattice of the subgroups of
+    the Galois group of an extension K/k and the lattice of intermediary
+    subfields of K
 
-- path: ./images/geodesic.tex
+- path: ./images/geodesic-min.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This picture represents the fact that geodesics locally minimize
-    distances
+  alt: A 2-dimensional sphere is marked by a violet curve connecting the north
+    pole to a point close to the equator. The violet curve runs across a
+    meridian, passing through the south pole along the way. On the left, a
+    circle highlights a small region around a point on the violet curve. In the
+    circle we can see a violet straight line representing the correspoding arc
+    of the violet curve and a winding dotted path joining its endpoints.
+  caption: "This picture represents the fact that geodesics locally minimize
+  distances: eventhough the violet great circle does not globally minimize the
+  distance between the marked points in the sphere, at each point in the
+  violet curve we can find a small neightborhood such that the purple arc in
+  this neightborhood minimizes the distance between the correspoing endpoints"
 
+# TODO: Track the source for this drawing? (i.e track the manuscript)
 - path: ./images/grothendieck-riemann-roch.tex
   license: PD
   author: Alexander Grothendieck
   author-url: https://grothendieckcircle.org/
-  alt: The commutative diagram from the Grothendieck-Riemann-Roch
-    theorem, surrounded by fire and two devils carrying forks
+  alt: A hand-drawn commutative diagram surrounded by fire and devils carrying
+    forks
+  caption: The infamous commutative diagram from Gothendieck's 1971 manuscript
+    on the Grothendieck-Riemann-Roch theorem
 
 - path: ./images/groups-periodic-table.svg
   # TODO: Figure out the actual license
@@ -103,26 +146,30 @@
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The Poincaré disc model of the hyperbolic plane
+  alt: A circle with an arc highleghted on its interior
+  caption: The Poincaré disc model of the hyperbolic plane
 
-- path: ./images/j-function.svg
+- path: ./images/j-function-relief.svg
   license: proprietary
   author: Eugene Jahnke & Fritz Emde
   source: https://archive.org/details/tablesoffunction00jahn/mode/2up
-  alt: Relief representation of the j-invariant elliptic modular
-    function
+  alt: Relief representation of a function of two variables
+  caption: Relief representation of the j-invariant modular function from the
+    book “Tables of Functions with Formulae and Curves”
 
-- path: ./images/j-function.jpg
+- path: ./images/j-function-color.jpg
   license: PD
   author: Jan Homann
   source: https://commons.wikimedia.org/wiki/File:KleinInvariantJ.jpg
-  alt: The j-invariant Klein function in the complex plane
+  alt: Domain coloring representation of a complex function
+  caption: The j-invariant Klein function
 
 - path: ./images/k4.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The complete graph of four vertices
+  alt: A triangle with marked vertices and a marked point on its barycenter
+  caption: The complete graph of four vertices
 
 - path: ./images/mobius.tex
   license: CC-BY-4
@@ -134,8 +181,8 @@
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The first columns of the chacter table of the monster simple
-    group in characteristic zero
+  alt: An increadibly big table of numbers
+  caption: The chacter table of the Monster simple group in characteristic zero
 
 - path: ./images/natural-number-line.tex
   license: CC-BY-4
@@ -143,77 +190,90 @@
   author-url: https://pablopie.xyz
   alt: The natural number line
 
-- path: ./images/ordinal-number-line.tex
+- path: ./images/real-number-line.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The ordinal number line
+  alt: The real number line
 
-- path: ./images/quaternion-rotation.tex
+- path: ./images/ordinal-number-line.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: "This drawing represents the correspondence between conjugation
-    by pure unitary quaternions and rotations in the 3-dimensional Euclidean
-    space: the coordinates of a unitary quaternion p number with zero real
-    coefficient induce a line through the origin in the 3-dimensional Euclidean
-    space, and conjugation by cos t + p sin t acts as rotation by 2 t around
-    this axis."
+  alt: "The ordinal number line: the natural numbers accumulate around ω,
+    followed by ω-translates of the natural numbers and so on"
+  caption: The ordinal number line
 
-- path: ./images/real-number-line.tex
+- path: ./images/quaternion-rotation.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The real number line
+  alt: A sphere with a rotation axis marked as "p". A curly arrow donotes
+    rotation by 2θ.
+  caption: "This drawing represents the correspondence between conjugation by
+    pure unitary quaternions and rotations in the 3-space: the coordinates of a
+    unitary quaternion number p with zero real coefficient define a line
+    through the origin in 3-space, and conjugation by cos θ + p sin θ acts as
+    rotation by 2θ around this axis."
 
 - path: ./images/real-ordinal-surreal-venn.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This picture represents the relationship between the real,
-    ordinal and surreal numbers
+  alt: Two circles, the first representing the real numbers and the second
+    representing the ordinal numbers, intersect in the middle of picture. Their
+    intersection is labeled as the set of natural numbers. A rectangle labeled
+    as the set of surreal numbers surrounds both circles.
+  caption: Venn diagram representation of the relationship between the real,
+    natural and surreal numbers (denoted by "No")
 
-- path: ./images/riemannian-metric.tex
+- path: ./images/sphere-metric-comparison.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This picture is a comparison between the Euclidean distance and
-    the Riemannian distance in a 3-dimensional sphere
+  alt: "A sphere is marked by two points and two curves connecting them: a
+    great circle and a straigh line passing through the interior of the sphere"
+  caption: "This picture is a comparison between the Euclidean metric and the
+    Riemannian metric of the 2-sphere: in 3-space the shortest distance between
+    the north pole and the point close to the equator is realized by the
+    straight line connecting them, but in the 2-sphere their distance is
+    realized by a great circle instead"
 
 - path: ./images/rigid-motion-reflections.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This picture represents the fact that reflections are rigid
-    motions
+  alt: Two squares with complex patterns in their interiors are placed side by
+    side, with a squily arrow pointing from the first square to the second
+    square. The pattern on the second square is a reflection of that on the
+    first square.
+  caption: Reflection on the y-axis
 
 - path: ./images/rigid-motion-rotation.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This picture represents the fact that rotations are rigid
-    motions
+  alt: Two squares and a curvy arrow representing the action of rotating one
+    into the other
+  caption: Rotation by 45° on the Cartesian plane
 
-- path: ./images/smooth-function.tex
+- path: ./images/manifold-charts.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This picture represents the definition of a smooth map between
-    manifolds
+  alt: Two small regions U and V in a surface M are highlighted, as well as
+    their intersection. On the bottom, a map labeled "φ_V ∘ φ_U⁻¹" indicates
+    the transition of charts.
+  caption: Transition of charts in a manifold M
 
-- path: ./images/smooth-manifold.tex
-  license: CC-BY-4
-  author: Pablo
-  author-url: https://pablopie.xyz
-  alt: This picture represents the definition of a smooth manifold
-
-- path: ./images/sphere-quotient.tex
+# TODO: Not sure I'm happy with this caption
+- path: ./images/smooth-function.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The isomorphism between the n-dimensional sphere and the
-    quotient of the (n + 1)-dimensional simple orthogonal group by the
-    n-dimensional simple orthogonal group
+  alt: A map f between two surfaces M and N with its representation in local
+    coordinates highlighted on the bottom of the figure
+  caption: A smooth function in local coordinates φ and ψ
 
 - path: ./images/sphere.tex
   license: CC-BY-4
@@ -225,63 +285,90 @@
   license: CC-BY-SA-3
   author: Drschawrz
   source: https://en.wikipedia.org/wiki/File:SporadicGroups.svg
-  alt: All the Sporadic groups in their subquotient relationship
+  alt: Graph representation of the subquotients of Sporadic groups
+  caption: "All the Sporadic groups and their subquotient relationships: an
+    edge from a group G on the top to a group H on the bottom means H is a
+    subquotient of G. Mathieu groups are collored red, Leech lattice groups are
+    colored green, other subquotients of the Monster are collored blue and the
+    rest of the groups are collored white."
 
 - path: ./images/square-to-circle-projection.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: "The projection from the square to the circle: we map a point in
+  alt: A circle and a square. A dotted ray connects the center of the square to
+    a point in the circle, passing through a point in the perimeter of the
+    square.
+  caption: "The projection from the square to the circle: we map a point in
     the square of length √2/2 onto the unit circle by normalizing it"
 
 - path: ./images/standard-sets-venn.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: This diagram represents the relationship between standard number sets
+  alt: Venn diagram representation of the containment relations between the
+    natural numbers, integers, rational number, real numbers and complex
+    numbers
 
 - path: ./images/stereographic-projection.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The stereographic projection
+  alt: A sphere sits on top of plane, with a line connecting the north pole to
+    the a point on the plane, passing thought another point in the sphere
+  caption: "The stereographic projection: for each point P in the sphere we
+    cast a ray from the north pole, identifying P with the point of
+    intersection of this ray and the plane just bellow the sphere"
 
 # TODO: Get the TikZ code for this somehow?
 - path: ./images/surreal-number-tree.svg
   license: CC-BY-SA-3
   author: Lukáš Lánský
   source: https://en.wikipedia.org/wiki/File:Surreal_number_tree.svg
-  alt: Visualization of the surreal number tree
+  alt: "A complex tree with vertices organized by stages and labelled by
+    different real and natural numbers"
+  caption: Visualization of the surreal number tree
 
 - path: ./images/tangent-space.tex
   license: CC-BY-4
   author: Gustavo Mezzovilla
-  alt: The tangent space of a smooth manifold at a point
+  alt: A surface with a highlighted point on its interior, together with the
+    plane tangent to the surface at that point
+  caption: The tangent space of a smooth manifold at a point
 
 - path: ./images/topology-mug-donut.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
   alt: A mug continuously morphing into a donut
+  caption: The homeomorphism between the surface of a mug and that of a donut
 
 - path: ./images/unit-circle-covering.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The universal covering of the unit circle
+  alt: A downwords spiral with a circle on its bottom and an arrow labelled "π"
+    pointing from the spiral to the circle
+  caption: "The universal covering of the circle: we can picture winding the
+    real line around the circle by identifying it with an infinite vertical
+    spiral whose “shadow” in the xy-plane is the circle"
 
 - path: ./images/unit-circle.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: The unit complex circle
+  alt: A circle with two highlighted points labelled "i" and "1"
+  caption: The unit complex circle
 
 - path: ./images/upper-central-projection.tex
   license: CC-BY-4
   author: Pablo
   author-url: https://pablopie.xyz
-  alt: "A graphical depiction of the central projection between the
+  alt: The upper cap of a sphere sits just bellow a plane, with a line
+    connecting the center of the half-sphere to the a point on the plane,
+    passing thought another point in the sphere
+  caption: "A graphical depiction of the central projection between the
     upper semi-sphere and the Euclidean plane: we map each point in the upper
     half of the sphere to the projection of this point in the tangent plane at
     the north pole by drawing a line between this point and the center of the
-    sphere and then taking the intersection of this line with the plane."
+    sphere and then taking the intersection of such line with the plane."

diff --git a/examples/images/geodesic-min.tex b/examples/images/geodesic-min.tex
@@ -0,0 +1,54 @@
+% This picture represents the fact that geodesics locally minimize distances
+% Copyright Pablo (C) 2021
+\begin{tikzpicture}[scale=0.5]
+  % The cirference
+  \draw (0, 0) circle (3);
+
+  % The equator
+  \begin{scope}
+    \clip (-3, 0) rectangle (3, -3);
+    \draw ellipse (3 and 1);
+  \end{scope}
+
+  % Greenwhich
+  \begin{scope}
+    \clip (-3, -3) rectangle (0, 3);
+    \draw ellipse (1 and 3);
+  \end{scope}
+
+  % The curve
+  \begin{scope}
+    \clip (-3, 0) rectangle (0, -3);
+    \draw[thick, color=violet] ellipse (1 and 3);
+  \end{scope}
+  \begin{scope}
+    \clip (3, -3) rectangle (0, 3);
+    \draw[thick, dotted, color=violet] ellipse (1 and 3);
+  \end{scope}
+
+  % The ends
+  \filldraw (0, 3) circle (2pt) (-1, 0) circle (2pt);
+
+  \draw (-0.87, -1.5) circle (0.3);
+  \draw (-1.17, -1.5) -- (-4, 1);
+
+  % Zoom in ares
+  \begin{scope}[shift={(-6, 1)}]
+    \draw (0, 0) circle (2);
+
+    % The geodesic
+    \draw[thick, color=violet] (0, -2) -- (0, 2);
+    \filldraw (0, -2) circle (2pt) (0, 2) circle (2pt);
+
+    % Another curve
+    \draw[dotted] (   0,    2) to[out=180, in=90] 
+                  (-0.6,  1.4) to[out=270, in=150] 
+                  ( 0.5,  0.7) to[out=-30, in=0] 
+                  ( 0.3,  0.1) to[out=180, in=180] 
+                  ( 0.5,  0.6) to[out=0, in=120] 
+                  ( 1.3,  0.7) to[out=-60, in=60] 
+                  ( 0.4, -0.5) to[out=240, in=90] 
+                  (   0,   -2);
+  \end{scope}
+\end{tikzpicture}
+

diff --git a/examples/images/geodesic.tex b/examples/images/geodesic.tex
@@ -1,54 +0,0 @@
-% This picture represents the fact that geodesics locally minimize distances
-% Copyright Pablo (C) 2021
-\begin{tikzpicture}[scale=0.5]
-  % The cirference
-  \draw (0, 0) circle (3);
-
-  % The equator
-  \begin{scope}
-    \clip (-3, 0) rectangle (3, -3);
-    \draw ellipse (3 and 1);
-  \end{scope}
-
-  % Greenwhich
-  \begin{scope}
-    \clip (-3, -3) rectangle (0, 3);
-    \draw ellipse (1 and 3);
-  \end{scope}
-
-  % The curve
-  \begin{scope}
-    \clip (-3, 0) rectangle (0, -3);
-    \draw[very thick] ellipse (1 and 3);
-  \end{scope}
-  \begin{scope}
-    \clip (3, -3) rectangle (0, 3);
-    \draw[very thick, dotted] ellipse (1 and 3);
-  \end{scope}
-
-  % The ends
-  \filldraw (0, 3) circle (2pt) (-1, 0) circle (2pt);
-
-  \draw (-0.87, -1.5) circle (0.3);
-  \draw (-1.17, -1.5) -- (-4, 1);
-
-  % Zoom in ares
-  \begin{scope}[shift={(-6, 1)}]
-    \draw (0, 0) circle (2);
-
-    % The geodesic
-    \draw[very thick] (0, -2) -- (0, 2);
-    \filldraw (0, -2) circle (2pt) (0, 2) circle (2pt);
-
-    % Another curve
-    \draw[dotted] (   0,    2) to[out=180, in=90] 
-                  (-0.6,  1.4) to[out=270, in=150] 
-                  ( 0.5,  0.7) to[out=-30, in=0] 
-                  ( 0.3,  0.1) to[out=180, in=180] 
-                  ( 0.5,  0.6) to[out=0, in=120] 
-                  ( 1.3,  0.7) to[out=-60, in=60] 
-                  ( 0.4, -0.5) to[out=240, in=90] 
-                  (   0,   -2);
-  \end{scope}
-\end{tikzpicture}
-

diff --git a/examples/images/j-function.jpg b/examples/images/j-function-color.jpg
Binary files differ.

diff --git a/examples/images/j-function.svg b/examples/images/j-function-relief.svg

diff --git a/examples/images/complex-lattice.tex b/examples/images/lattice.tex

diff --git a/examples/images/smooth-manifold.tex b/examples/images/manifold-charts.tex

diff --git a/examples/images/riemannian-metric.tex b/examples/images/sphere-metric-comparison.tex

diff --git a/examples/images/sphere-quotient.tex b/examples/images/sphere-quotient.tex
@@ -1,30 +0,0 @@
-% This picture represents the isomorphism between the n-dimensional sphere and
-% the quotient of the (n + 1)-dimensional simple orthogonal group by the
-% n-dimensional simple orthogonal group
-% Copyright Pablo (C) 2023
-\begin{tikzpicture}[scale=0.5]
-  % The sphere
-  \begin{scope}
-    \clip (-3, -3) rectangle (3, 2.625);
-    \draw (0, 0) circle (3);
-  \end{scope}
-
-  % The equator
-  \begin{scope}
-    \clip (-3, 0) rectangle (3, -3);
-    \draw ellipse (3 and 1);
-  \end{scope}
-
-  % Greenwhich
-  \begin{scope}
-    \clip (-3, -3) rectangle (0, 2.625);
-    \draw ellipse (1 and 3);
-  \end{scope}
-
-  \draw (-3, 2.625) -- ( 1.5, 2.625)
-                    -- (   3, 3.375) node[right]{$T_p \mathbb{S}^n$}
-                    -- (-1.5, 3.375)
-                    -- cycle;
-  \filldraw[black] (0, 3) circle (2pt) node[right]{$p$};
-  \draw (0, 3.375) node[above]{$\operatorname{SO}_n$};
-\end{tikzpicture}