On Thu, 20 Dec 2018 07:09:59 -0000, Daniel60 wrote:

Mark Lloyd wrote on 20/12/2018 3:21 AM:
On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under
the LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.
... and, in real life, the Mag wheels of some cars seem to be spinning
backwards, dependant on the speed at which the car is travelling!!

In real life? I assume you mean under streetlighting. That effect can't occur with a steady lightsource such as the sun.