The problem is how long time it would take until the pond is covered in water lilies. The princess and frogs are there to arouse curiosity and provide a good mood
Book-cover. Some characters from the book break out through the cover. To attract interest, invite to browse and then hopefully find something else inside.
Beware of the moose! Meant to illustrate a calculation of how may pupils dared to stay
Downhill skiing, mountains, snow two mathematical problems