视错觉立方体
它是一个房间里的小立方体，还是一个缺了一个角的大立方体？
画出这个立方体，比用文字描述如何画它要容易得多！我们使用方格纸（徒手！）绘制构成该立方体的线条：外层立方体每边画六格，内层立方体每边画三格。绘图时须严格遵循步骤说明，唯有如此，每位同学才能成功完成这一视错觉立方体！
铅笔稿完成后，我们为每组选定了两种颜色，每种颜色各取深、中、浅三个明度（例如：绿色记号笔——深绿、中绿、浅绿；红色记号笔——深红、中红、浅红）。
依据空间的三个方向，我们用所选颜色为棋盘格着色（第一侧面用两种深色，第二侧面用两种中色，第三侧面用两种浅色）。
Optical illusion cube
Is it a small cube in a room or a large cube that lacks one corner?
Is easier to draw this cube, rather than to describe in words how to draw it ! We used a squared paper to draw (freehand!) the lines that create the cube, counting six segments to the outer cube and three for the inner cube. While drawing you have to follow the instructions carefully, only in that way it will be possible for everyone to realize this op cube!
When we finished the drawing in pencil, we chose two colours in three different shades: dark-medium-light (eg: 3 felt tip pens green dark-medium-light and 3 felt tip pens red dark-medium-light).
Following the three directions of space we colored the chessboards with the colours chosen (the two darkest colours for the first side, the two medium colours for the second side and the two lightest colours for the third side).
