1. Stars (GER):
In winter and christmas time stars are a good topic to do some maths about angles and and relation between regular stars or polygons as well. 

2. Flowers (LATVIA):

See more in the GeoGebra Book

3. Caleidoscopes (GER)

See GeoGebra Book

3. Animated flowers -using polygons/circular arches (RO)

GeoGebraBook