2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/96822We present a new visualization of the proper-time elapsed along an observer's worldline. By supplementing worldlines with light clocks, the measurement of space-time intervals is reduced to the "counting of ticks." The resulting space-time diagrams are pedagogically attractive because they emphasize the relativistic view that "time is what is measured by an observer's clock."11 pages, 14 figures, to appearPhysics Educationtext