Clients and creative directors are daily hazards faced without flinching by agency account handlers across the globe.

But puff adders ... ?

No flinching there either. They're made of stern stuff at Net#work BBDO in Johannesburg, the perpetrator of a spectacular April Fools Day hoax that has become a talking point across Africa's most prosperous nation.

No fewer than seven crop circles that appeared, seemingly overnight, in the maize field of a farm in Heidelberg, had South Africans baffled as 'breaking news' bulletins played out on TV screens across the country last week and millions debated whether they were the work of psychic forces or aliens from Alpha Centauri?

The truth, as it eventually emerged, was less exciting. The circles were simply a potent way of reinforcing the brand logo of South African cellphone network Cell C, whose logo was formed by the circles' strategic siting.

Net#work BBDO executive creative director Julian Watt reveals all: "Once we had convinced a farmer to let us use one of his fields, we soon found out how difficult it is to create seven 30 metres diameter perfectly aligned circles, taking up a total area the size of three rugby fields, among maize that is over nine feet tall.

"Then both farm workers and Net#workers, narrowly escaping puff adders, physically stomped on enough maize to create the client's logo. And the genuine-looking farmer testifying to the circles? Well, he was actually a policeman."

Cell C marketing head Simon Camerer approves of the romp, saying it matches the brand's profile exactly - fun and cheeky. Meantime, Net#work BBDO is capitalizing on its handiwork as the creator of South Africa's largest 'fly-over billboard'.

It is negotiating with domestic airlines to make a special onboard announcement alerting passengers to view the massive "C For Yourself" spectacle, as they overfly the circles.

Data sourced from (South Africa); additional content by WARC staff