On Display

Elka 101, electronic pocket calculator, 1976.

Electronic Pocket Calculator by Isot, model Elka 101, c1976. Before the fall of the Iron Curtain in 1989, Bulgaria hasd one of the largest electronics industries in Eastern Europe. However in the 1970s they had to import the integrated circuits to co

 
Mechanical counting device, c 1900.

Mechanical counting device, c 1900. Devices for counting the revolutions or repetitive actions of machines were developed from the mid 19th century.

 
Smith and Dolier's arithmetical scales, late 19th century.

Set of 'arithmetical scales' by Smith and Dolier, late 19th century. These 'scales' were used to set many different sums in addition and subtraction. Pupils in a class would probably have used slates to do the sums.

 
Klein bottle, 1995.

A single surface model made by Alan Bennett in Bedford, 1995. It is a Klein bottle which has been cut to form two single-twist Mobius strips. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed in t

 
Klein bottle, 1995.

A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle cut to form one four-twist band. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed in three dimensions.

 
Klein bottle, 1995.

A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle cut to form two interlinked three-twist Mobius strips. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed

 
Klein bottle, 1995.

A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle cut to form one single-twist Mobius strip. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed in three d

 
Klein bottle, 1995.

A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle cut to form one single-twist Mobius strip. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed in three di

 
Klein bottles, 1995.

Single surface models made by Alan Bennett in Bedford, 1995. Four small Klein bottles (left to right): i) one loop relating to the single-twist Mobius strip, ii) two loop relating to the three-twist Mobius strip, iii) three loops relating to the five

 
Klein bottle, 1995-1996.

A Klein bottle is a surface which has no edges, no outside or inside.