the standard explanation for hoaxing is bullshit, been proven you can't do the complex ones that quickly, that neatly in the dark, like the guys "The Sun" tabloid newspaper went on about.
Would take a dedicated, very skilled GROUP of people to do these fast enough and precisely
note it's at night, farmers never caught enyone, sometimes pitch black when it's been done.
Personally I think it's some military or ex-military types , or maybe some university group of long standing, as you need
1) Night Vision goggles, you can't bloody do that stuff otherwise in the dark, and considering how many years ago this started, only the miltiary or wealthy could get hold of such (has been done in dark of the moon, you try finding yer way around a field when it's pitch black, lol! rememebr, no torches, or they'd be seen)
2) A damn good artist!! One with probably high degree of mathemaical skill, could even be created by a custom program on a computer (ie like fractals)
3) Takes very high degree of co-ordination of people to do this. Most folk cannot organize a p*ss up in a brewery! Never minf do this for decades, not get seen, do it even onmoonless nights, do it over a large area with extreme precision.
So, wouldn't be surprised if it's some prank, initation right or such, of military/university/group of close, dedicated friends.
they are bloody amazing art, regardless of origin
thanks for posting!