Contour plot of lapse and shift vector for a boosted Schwarzshild black
hole (Eddington-Finkelstein coordinates)
with the contours depicting levels of constant lapse and the line segments
depicting the size
and direction of the shift vector. The hole is traveling at
0.5c up this page. The lapse is smaller ahead of the hole
than behind, thus the hole moves through the computational grid.
The ovoid is the apparent horizon, distorted in