Einstein as a speed devil - science puzzle
|How fast should you drive towards a red traffic light to see it appear as green?|
Somewhere on a sphere - math puzzle
What is the mean distance between two randomly choosen points within a sphere of radius 1?
Platonic solids - math puzzle
|Show that there exist only five platonic solids (that are objects which are build out of the one sort of regular polygons, like the tetrahedron and the cube). Hint: use that for each solid in three dimensions it holds that the number of vertices + the number of faces is equal to the number of edges + 2.|