The difference of two cubes. Typeface is Tuffy (public domain, created by Thatcher Ulrich) from openfontlibrary.org 多維資料集 差異 相對補 兩個多維資料集的差異
Cleaned up a trace of http://en.wikipedia.org/wiki/File:Dead_Tree_Silhouette_with_Sunset.JPG , which is in the public domain. 樹 枯樹 初秋的樹 死樹 Silhoutte
Ball-and-stick model of graphene, drawn in Inkscape. I had to reduce the amount of repetitions on the structure (note that graphene can have an infinite amount of repetitions of the benzene ring motif), due to a bug in OCAL's previous website that was breaking the SVG submission process when the number of "rows" got higher than six. 化工 石墨烯 有機 石墨烯
dead apple tree cartoon winter trees plant life die bare barren lifeless Bare Dead Tree clip art 裸 死 樹 裸死樹剪貼畫