A retrographic sensor includes a flexible transparent structure, a transparent elastomeric pad, and an at least partially reflective layer. The flexible transparent structure may be configured to elastically deform between multiple configurations. At least one light source emits light into the transparent structure. The flexible transparent structure may include one or more markers that are illuminated by the at least one light source. The retrographic sensor may also include a photosensitive detector configured to image the flexible transparent structure and one or more markers. A processor may determine a configuration of the flexible transparent structure based at least in part on an image from the one or more markers.