[header] How to draw an impossible cube [title] Draw a skinny, vertical parallelogram with the lower left corner open; from there, draw two lines going horizontally, shown in red. [title] Add two connecting lines on the right side of the parallelogram. [step] They should form an " l ". 
[title] Add another two lines which continue from the corner of the parallelogram but pass beneath its right edge. [step] The two lines then separate vertically, one going up and another going down to meet with the end of the " l ".