One hundred unit variance normally distributed measurements—zero mean (+) except for a block of events 25–75 (dots). In the four panels the block amplitudes are 0.2, 0.32, 0.5, and 1.0 in units of the Arias-Castro et al. (2005) threshold ﹩\sqrt{\ 2 \ \log N}﹩. Thick lines show the blocks, where detected, with thin vertical lines at the change points.