Crop circles might be known for their beauty and paranormal allure, but the giant phalluses etched into the field of a Hamilton high school hold no such mystique.
Fairfield College has been snapped by satellite cameras with six huge penises burnt into the grass.
The x-rated images, immortalised on the website Google Earth, were spotted by Kiwi David McQuoid while scanning the neighbourhood online looking for a property.
"At first I thought it was a large piece of artwork," he said of the shot, which shows cartoon-like phalluses of various sizes, some several metres across.
Publicity around the so-called Fairfield Phalluses has embarrassed the school's acting principal Gerhard van Dyk, who told the Waikato Times it was hard enough to deal with when the prank was pulled back in 2009.
It happened over a weekend but it wasn't until the grass died off bit by bit that phallic symbols started to pop up around the school grounds.
Every week another crude image revealed itself, much to the dismay of staff.
"There's not really much we could do about it," he told the newspaper.
"The caretaker took some more weedkiller and tried to camouflage it a bit."
Mr van Dyk never caught the culprits and the prank would no doubt have passed into schoolboy folklore had it not been captured by Google Maps.
The red-faced principal said he would be contacting Google to plead for the image's removal but an internet privacy specialist said it was difficult to get such satellite photographs changed or blurred.
Kiwis however, thought the prank was hilarious, with 70 adding mostly encouraging comments to the online story, like "Freakin brilliant!!! Love it!!! Classic piece of adolescent artwork."
One gave the artists an A+, top marks for cunning, planning, chemistry and geometry, while another said their anatomy detailing left a lot to be desired.
"I totally reckon it was actually girls," they wrote. Then came a confession: "HAHAHA!!! we did this as our 7th form prank, now it lives on! how awesome!"