1. A computer-implemented method comprising: identifying, using one or more computing devices, a field in a set of forms and strokes included in the field; determining, using the one or more computing devices, distance metrics between the strokes; creating, using the one or more computing devices, a hierarchical cluster for the strokes included in the field based on the distance metrics; receiving a search query from a first user, the search query including a first stroke extracted from the field of a form filled out by a second user; retrieving, using the one or more computing devices, a cluster from the hierarchical cluster and example strokes of the cluster similar to the search query; providing the example strokes to the first user; receiving, from the first user, a selection of a first example stroke from the provided example strokes; and responsive to receiving, from the first user, the selection of the first example stroke, retrieving a table listing a number of forms in the set of forms that were filled out by the second user and have strokes similar to the first example stroke.
9. The method of claim 1 , wherein the search query includes text; and wherein retrieving the cluster comprises converting the example strokes of the cluster to symbolic representations, determining that the symbolic representations match the text included in the search query, and retrieving the cluster based on the match.