Choose a lattice. A target appears and remains until you triple-click quickly, then eight options appear, ordered left-to-right by perturbation strength. Every finite graph edge is independently displaced perpendicular to itself by Gaussian noise. The correct option has the same SD as the target but a different noise realization; the leftmost option is always zero perturbation.
On the target, triple-click quickly to continue. On the options, respond by clicking an option or pressing 1–8. Type show to reveal without answering. Press R for a new trial, Esc for this menu.