Christmas tree
I built this Christmas tree by request. It is based on a structure of parallel layers used in several models at the Geomag Gallery (in the album Celebrations), although I think that I saw it for the first time in the webpage of Peter Jepsen, now unavailable.
GEOMAG constructions: Christmas tree, view 1
Christmas tree, view 1
4424 pieces: 933 balls, 2556 rods, 15 pentagons, 115 squares, 805 triangles (20.79 kg)
(including a non-standard, bigger ball)
GEOMAG constructions: Christmas tree, view 2
Christmas tree, view 2
The trunk is a tower made of pentagonal prisms, which becomes double-scaled at the bottom. It is very easy to add vertical color rods to the edges of the layers, as if they were small candles; it is also easy to hang different ornaments from the lower, widest layer of each stage. However, the whole thing doesn't seem very strong to me, so I wouldn't add much more weight.