  Unary coding is useful but it is redundant in its standard form. Unary coding
can also be seen as spatial coding where the value of the number is determined
by its place in an array. Motivated by biological finding that several neurons
in the vicinity represent the same number, we propose a variant of unary
numeration in its spatial form, where each number is represented by several 1s.
We call this spread unary coding where the number of 1s used is the spread of
the code. Spread unary coding is associated with saturation of the Hamming
distance between code words.
