Another Graphic Solution of Differential Equation of the Second Order
Car Rally
Construct a Counterexample to Sorites
Decomposition on Double Triacontahedron
Equivalential Formula
Expanding Ball of 30 Octahedra
Folding Schwarz's Polyhedron
Four Sign Changes
Total Variation of Function
Function Identification Game
Graph of Relation under Coordinate Transformation
Graphic Solution of a Differential Equation of the First Order
Graphic Solution of Differential Equation of the Second Order
Gyroelongated Square Dipyramid to Tetrahedron Net Dissection
Icosahedral Rotational Symmetry Types
Lukasiewicz's Three-Valued Modal Logic
Mass Center of a Truncated Cylinder
Measure of Asymmetry of Strongly Binary Trees
Net for Schwarz's Polyhedron
Nomogram of x/a+y/b
Nonograms From Mathematica Characters
Nonograms From Pixelization of a Font
Octahedral Rotational Symmetry Types
Octahedron Tessellation
Polyhedral Maps
Replacing Rhombohedra in Hexecontahedron
Signed Area of Parallelogram or Triangle Test
Solvable Nonograms
Steinitz's lemma
Surface of a Cube to Surface of Tetrahedron Dissection
Surface of Octahedron to Surface of Terahedron Dissection
Completeness Theorem of Equivalential Calculus
The Completeness Theorem of Equivalential Calculus
Total Variation of Function
Twist-Hinged Dissection of Hexagram to Two Hexagons
Two-Cube Calendar
Two Views Maze
Some Unistable Polyhedra
Vernier Caliper of Precision 0.05 mm
Izidor Hafner, January 2014