From his strange perch, amid the exhaust fumes and general racket of ceaseless traffic, he is counting down the hours to the end of the millennium. As each hour slides past, he walks along a little gangplank in front of the board and changes the figure. By the time you read this it should be below 100.
And for the rest of this week he will carry on doing so, completing a modest feat of endurance he hopes will earn him a place in The Guinness Book of Records - or "Jinis", as he calls it - as the world's only human millennium clock. But, unlike many entries in that book, his is not an utterly pointless endeavour.Through a sponsored promotion, organised by a radio station, Radius, Yair Revivo, 24, will earn a three-year grant of 30,000 shekels - pounds 4,225 - for tuition fees to study law at Bar-Ilan university if he makes it to 1 January.
Or rather, he and his dad, Yakov, an aircraft engineer; his mother fretted so much about safety during the nights that she ordered his father to stay with him, squeezing into the tiny tent to sleep. They now share hour-changing duties.
It is, to be sure, a better way of paying his way than his old job of waiting on tables. It is certainly not boring - he has a computer rigged up inside his tent, through which he has received over 150 electronic messages and on which he can watch himself on his own site. (www.any1home.com)
But all has not gone entirely smoothly. When Yair set up his camp 11 days ago, there were four accidents, as drivers rear-ended one another. Now the radio station is putting out warnings to those passing by.
Let's hope he is better as a lawyer than he is at time-keeping. For - truth be told - he is not much of a clock. When he marked the 176th hour, bellowing at the cars like an Elizabethan watchman, I couldn't but notice it was already 20 past four.