Calculator spelling

O I or l Z E h
S g L B G
Inverted calculator digits and their letter equivalents

Calculator spelling is an unintended characteristic of the seven-segment display traditionally used by calculators, in which, when read upside-down, the digits resemble letters of the Latin alphabet. Each digit may be mapped to one or more letters, creating a limited but functional subset of the alphabet, sometimes referred to as beghilos (or beghilosz).