  Blisters are commonly observed when an adhesive sheet is carelessly deposited
on a plate. Although such blisters are usually not desired for practical
applications, we show through model experiments on angular blisters how
material properties can be deduced from height profile measurements. In
particular the typical curvature of the crests is found proportional to an
elasto-capillary length that compares the bending stiffness of the sheet with
adhesion energy. In addition, the radius of the tip allows to estimate the
product of this length with the thickness of the sheet. The relevance of these
results to realistic random configurations is finally confirmed.
