The Caran d'Ache Fixpencil has been tucked behind the ears of renowned architects, including Mario Botta, for almost a century. To show his appreciation for his instrument of choice, the prolific Swiss post-modernist has created two limited-edition, chequered versions, with a new case to match.

Invented in 1929 by Swiss engineer Carl Schmid, Fixpencil was the world's first mechanical writing tool fitted with a patented clutch mechanism. It was also an early iteration of the 'pencil for life'; a concept that emerged as a result of Switzerland's dwindling cedar wood supplies. Architects and designers did not want (or could not afford) a new wooden pencil each time their old one stubbed-out, so Schmid provided a lead-replenishing solution. Since its conception, in excess of 25 models of the Fixpencil have been developed, each enjoying deserved global success.

For Botta, the Fixpencil is more than just something to sketch with. He sees the instrument as an extension of his hand, and goes so far as to say that it facilitates 'a direct link between thought and the result on the paper'. It is, he continues, a 'genuine source of inspiration'.

He chose a monochromatic design for the two new editions, one predominately white and the other black. Botta intended the checkered effect to 'highlight the comfortable hexagonal structure' of the pencil's body, and was inspired by a contrasting overlay of bricks – his favourite material to work with. It's no secret that this new Fixpencil launch coincides neatly with Snøhetta's redesign of SFMoma, where Botta's broad-shouldered 1995 brick addition to the musuem remains intact.

Indeed, the brickwork is integral to the pencil's design. Five of the blocked out tiles on the pencil's stem equal 1cm, so the tool doubles up as a handy ruler.

The hexagonal case is just as multifunctional. As well as being housed in an attractive, architecturally structured box (making it a lovely, geeky gift idea), once opened the case becomes a convenient desk-tidy, to hold the instrument and its accompanying, colourful lead sticks.