Whilst going about our daily lives we all leave behind worldlines in spacetime: the four dimensional blend of space and time within which events unfold.
Worldlines are ghostly, insubstantial filaments, silken yarns that follow us through our lives forever. They cannot be seen or felt. If worldlines could be visualised then I imagine they would look like incredibly complex versions of light paintings.
Below is a light painting by the american photographer and visual artist Barbara Morgan (1900-1992): Pure Energy and Neurotic Man (1940).