These are the faces of postwar UK prime ministers merged into one

Photographer Alejandro Almaraz has created a series called Portraits of Power which superimposes the official portraits of successive heads of government over a period of time.

Art and photography critic Vicky Goldberg explains that it is startling how Almaraz's works - each overlaying between four and 40 photographs - show that the "presentation of officialdom stays remarkably consistent within one nation over many years".

"Though the presidents of any nation change with time - revolutions, coups, politics, elections, and death - the depictions and symbols of authority march on essentially unchanged," she explained.

With the majority of non-royal rulers opting for dark-coloured suits, Goldberg notes that of all the compositions "the most intrusive difference is a hint of blouse, pearls, and hair-do left over from Margaret Thatcher".

Although the "presentations of power" remain largely the same, there appears to be little similarity in the faces of the leaders - leaving each country's portrait with a certain distinctiveness.

As Slate notes, with Almaraz's methodology, even leaders who have ruled for many, many years and made a huge impact on a country's history are lost in the blur of their predecessors and successors - perhaps signifying the "fleetingness of power".

Several attempts over the ages have attempted to develop the "normal" face of a certain type of personality trait - from leadership to criminality - but with little success.

Put enough individuals together and you get a faceless crowd, bind enough presidential portraits to each other and you get… nobody recognisable.

What’s left are the residue of symbols, or symbols themselves, the creation of which, after all, is another talent in the medium’s nearly endless endowment.

• Vicky Goldberg

More: Online storytelling never looked so good

Alejandro Almaraz's "Portraits of Power" will be on display at the Art Museum of the Americas in Washington DC from 6 November, you can see the full set on his website here.