This can be easily seen by removing the center dot and dividing the rest of the figure into four triangles, as below:

You see a blank or dark spot (other than the center dot).

He had no choice now but to draw a line from the center dot to one of the sides.

Collins placed the officer's throat equidistant between the man's heel and the center dot of the reticle.

Covering one eye at a time, look at the center dot of the grid.

Originally, drummers favored single-ply drum heads with a center dot for these drums.

The "center dot below" may not always be available.

Cover one eye and stare at the center dot in this Amsler Grid, from a distance of 12 to 15 inches.

The ant-lion reached across and scraped another line, from Grundy's center dot to the other corner dot.

The center red dot is an automatic three outs and the surrounding area is an automatic hit.