Figure 6: We have shown here various string profiles in -plane. The vertical axis is the -axis and the horizontal axis is the -axis. The left diagram corresponds to and the semicircular profiles shrink as time increases towards positive values. On the right, we have and the semicircular profiles grow as time increases. In both, the advanced solution is denoted by the blue, thin curve and the retarded solution is represented by the red, thick curve. The green horizontal dashed line corresponds to the worldsheet event horizon, located at . We have taken these diagrams from [50], with the authors’ consent.