Synchron of a traveling feature-thing

There is a Target, emitting waves from
(x,y,z)= (2,2,10) inches.

The graph of points (M,T) of times-of-arrival T of a traveling feature-thing

at Sensors M. The "Angle" to the Target is off the vertical line through (0,0),

the upper-left corner of the (x,y,0) grid of Sensors.

Vertical differences are exaggerated