| Content |
| Startpage |
| Mathematic |
| Golden Ratio |
| Pi geometry |
| Squaring the Square |
| Magic square of 3. Order |
| Magic square of 4. Order |
| Informatics |
| Tangram |
| Sudoku calculation |
| N-Corner Frisbee |
| L-game |
| Logic Tower |
| Rubik Cube Pattern |
| Escher Cubes |
| Nature / physics |
| Golf - GPS accuracy |
| Golf - putting on a slanted green |
| Golf - putting on a stepped green |
| Corona pandemic |
| Flight to the Moon |
| Einstein's theory of relativity |
| Technique - Technology |
| Thick optical lenses |
| Depth of field |
| Excentric coaxial cable |
| Force on live wires |
| Gunn-oscillator |
| 1 + 1 = ??? |
| Heating optimization |
| New: Puzzle Escher Cubes |