Work out what Alex has on top of his head

Alex Horne in a large-brimmed straw hat, peering over the geodesic dome.

Task types:

Solo

Filmed

Mental

Physical

Objective

Single brief

Original

Locations:

Taskmaster House (UK)

Spaces:

The Garden (Taskmaster UK), The Driveway (Taskmaster UK), The Caravan (Taskmaster UK), The Dome (Taskmaster UK)

Task brief

The task brief is attached to the hand of a cardboard cut-out of Alex Horne, standing on the driveway next to the geodesic dome. The brief for the task is as follows:

Work out what Alex has on the very top of his head.

The very top of your head must never be more than five foot six inches from the ground.

You may ask Alex ‘yes’ or ‘no’ questions, but Alex will only answer using his exciting new numbers system.

Fastest wins.

Your time starts now.

A cardboard cut-out of Alex holding the task envelope on a raised hand.

Task notes

The cardboard cut-out of Alex Horne features a speech bubble coming from his mouth, containing the text ‘No higher than this.’, and Alex is holding his hand out to the side and just above the top of his head, indicating the height restriction (and playing into Greg’s long-running joke that Alex is only 5’ 4” tall).
The real Alex Horne is sat on top of a umpire’s chair inside the geodesic dome, with his head through a hole in the top where one of the dome’s panels has been removed.
Alex is wearing what appears to be two wide-brimmed sun visors upside-down on his head, preventing anyone from being able to see what is on top of his head from any angle.
He also wisely has a pair of safety glasses on him, just in case the contestants start trying to knock his hat off.
Alex speaks to the contestants through a small loudspeaker, only answering their ‘yes’ or ‘no’ questions with numbers.
It turns out that Alex responds with a prime number to mean ‘yes’, and a composite number (i.e. not a prime number) to mean ‘no’.
A pair of Alex’s shoes have for some reason been left at the foot of the cardboard cut-out, and contain sanitary towels. In an outtake from the episode, Alex confirms that he puts sanitary towels inside his shoes in order to prevent blisters, so this apparently has no significance to the task itself.
There is a small periscope mounted through the roof of the caravan, which allows the contestants to see a sign on top of the caravan which reads ‘BEHIND GREG’.
If the contestants look behind Greg’s statue in the garden, there is a much taller periscope made from drainpipes which they can use to look at the top of Alex’s head.
It turns out that Alex has a plastic carrot attached to the top of his head with a hairband.
One of the pairs of socks which Alex is shown wearing during this task (in particular, during Fatiha's attempt) was designed by the YouTuber Hank Green, and sent to Alex Horne in the hope that he'd be able to wear it at some point during the show.