Notice that you are trying to draw Venn diagrams using only rectangles. http://en.wikipedia.org/wiki/Venn_diagram Check: http://www.combinatorics.org/Surveys/ds5/VennOpenEJC.html It states that it is an open problem whether it is always possible to construct a Venn diagram using congruent curves, and particularly, if it is possible to draw a 6-Venn diagram in which each curve is a rectangle.