All examples here fit left in BP369, a version where the figure is allowed to pass through itself while being deformed.
Adjacent-numbered pages: BP846 BP847 BP848 BP849 BP850  *  BP852 BP853 BP854 BP855 BP856
math, traditional
figure_made_of_curves_and_quotient_by_hollow_dots [smaller | same | bigger]
Aaron David Fairbanks
See BP851 for a version where the figure must stay within the 2D plane and cannot pass through itself while being deformed.
Adjacent-numbered pages: BP364 BP365 BP366 BP367 BP368  *  BP370 BP371 BP372 BP373 BP374
nice, math, traditional
zoom in left (figure_made_of_curves_and_quotient_by_hollow_dots)