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Dan Reznik @UCJ3BPNdm0z1UzcJYTwxlsjA@youtube.com

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Exploring the Dynamic Geometry, Properties, and Invariants o


01:41
Poncelet triangles about the incircle, containing an equilateral: loci of several triangle centers.
01:58
Circle-inscribed Poncelet triangles with an equilateral: locus of the vertex of the Kiepert parabola
01:16
Circle-inscribed Poncelet triangles with an equilateral: stationary X(110)
04:36
Circle-inscribed Poncelet triangles w/ an equilateral III: the locus of the inconic centers
05:32
Circle-inscribed Poncelet with an equilateral II: the double stationarity of X74, X110
06:23
Circle-inscribed Poncelet triangles with an equilateral I: the X(3)X(74) axis is stationary
02:43
Poncelet triangles between two ellipses: properties of the locus of the orthocenter X(4)
01:47
Poncelet Triangles with Circular Caustic: The loci of X2, X4, and X7.
01:26
Four special Poncelet triangle families (circular caustic): focal-X1, iso-X2, focal-X4, and focal-X7
02:13
Poncelet Triangles with Circular Caustic: The loci of X3, X5, and X8.
05:56
MacBeath Poncelet family: vertex and area centroids are stationary; perimeter one sweeps ellipse
03:33
Three Poncelet triangle families with stationary orthocenter X(4)
05:38
Poncelet triangles with fixed barycenter: choosing the caustic
05:53
Poncelet Polar-to-Harmonic Polygons: sum of tangents of half angles is conserved
06:49
Poncelet triangles w/ circular caustic X: a family with fixed barycenter and Nagel line
02:10
Bicentric Poncelet N=5: polar polygons conserve the sum of half-angle sines
02:59
Poncelet triangles w/ circular caustic IX: the "orthofocal" circumellipse, loci and an invariant
03:27
Poncelet triangles w/ circular caustic VIII: inverse-in-incircle of circumcircle
05:40
Isocurves of area for envelope of ellipse bisectors III: circular domain
12:41
Isocurves of area for envelope of ellipse bisectors II: more cases, self-intersections, etc.
04:01
Isocurves of area for envelope of ellipse bisectors I: Q1 is a focus
02:07
MacBeath Poncelet N=3: Inversive image of sidelines wrt circumcircle conserves sum of 1/(ri^2)
04:51
Inversive image of Bicentric Polygons II: N=5 conserves perimeter (sum of arclengths)
05:05
Inversive image of Bicentric Polygons I: sum of arclengths (perimeter) is conserved
01:56
Poncelet triangles w/ circular caustic VII: foci of X(3) locus dependence on C
06:50
Poncelet triangles w/ circular caustic VI: nifty circular locus of X(36)
06:08
Poncelet triangles w/ circular caustic V: honey, I shrunk the triangle centers!
05:36
Poncelet triangles w/ circular caustic IV: amazing foci of the circumcenter locus
04:46
Poncelet triangles w/ circular caustic III: the loci of X2,X3,X4,X5
12:31
Poncelet triangles w/ circular caustic II: loci of centers over caustic centers
03:07
Poncelet triangles w/ circular caustic I: level curves of caustic radius
01:27
MacBeath Poncelet Family (even N): diagonals meet at a point
03:25
MacBeath Poncelet N=4: sidelengths vs. Poncelet parameter
03:45
Poncelet MacBeath N=3 Conservations and Spherical Curve of the Sidelengths
02:40
Conservations of "MacBeath" Poncelet Polygons: sum of squared sidelengths and double-angle cosines
04:19
Conjecture for the locus of X1 (incenter) over Poncelet triangles: a conic iff the pair is confocal
02:32
Conservations of MacBeath Poncelet triangles vs. the confocal (elliptic billiard) family.
05:55
Locus Invariants of Circle-Inscribed Poncelet Triangles IX: X2 and X4 and the outer projected conic
05:22
Locus Invariants of Projected Poncelet Bicentric Polygons VIII: vertex and area centroids
05:10
Locus Invariants of Projected Circle-Inscribed Triangle Families VII: over all nested caustics
06:01
Locus Invariants of Projected Poncelet Triangles VI: sliding bicentric caustic
07:24
Locus invariants of projected Poncelet triangles V: rotate outer conic about circular caustic: bad!
06:40
Locus invariants of projected Poncelet triangles IV: rotating concentric and MacBeath inellipses
08:06
Locus invariants of projected Poncelet triangles III: rigid rotations of generic caustic
03:36
Locus invariants of projected Poncelet triangles II: rotating Chapple's circular caustic
16:25
Locus invariants of projected Poncelet triangles I: Chapple's porism w/ a rotating caustic
02:34
Strophoids IV: a hidden equilateral
05:23
Beautiful MacBeath Poncelet N=5 (II), caustic a semi-confocal hyperbola, 5 concyclic points
13:55
Strophoids III: locus of the foci of inconics to a complete quadrilateral
07:06
Strophoids II: a special strophoid triad associated with a triangle and its intouch triangle
09:49
Strophoids I: construction, finding the focus
13:39
Beautiful MacBeath Poncelet N=5 (I): diagonals meet on a circle of 5 points
04:19
Poncelet n=4 between two identical unit circles
04:04
[see proof] Permutation Ellipse VI: Circumellipse area invariant under center permutations
06:15
Permutation Ellipses V: The Self-Permuting Sextic
11:37
Permutation Ellipses IV: Equal Area Circumellipses and a Sextic Locus
08:19
[see challenge] Permutation Ellipses III: P on the Steiner Circumellipse and Homothetic Poncelet
06:54
Permutation Ellipses II: doubling up, quintuple tangencies, straight loci (read note)
05:41
Permutation Ellipses I: locus of permutations over P on circumcircle
14:53
ICGG2022 [full]: "The Wrought-Iron Beauty of Poncelet Loci"