Induced edge singularities
¨
Y
X
d
unstretchable
To avoid stretching,
Border Y of bent region must extend straight to edge
Dominant energy  E prefers minimum dihedral angle a:  E ~  a7/3
a
d = 0
end view
bottom
smallest a
least energy
strong curvature: induced vertex...
induced vertex Þ
sharp edge
large d
imposed foci
generate
further foci