The language had a number of idiosyncrasies of its own. In contrast to later versions, the codice_3 command was required on all statements lacking another command, so was not valid in this version. The codice_4 statement used the comma when printing multiple variables, advancing to the next of five "zones". The comma was not needed in the case where one was printing a prompt and single value, so was valid. A somewhat hidden feature was that all variables were capable of representing arrays (vectors) of up to ten elements (subscripts 1 to 10, changed to 0 to 10 in the Second Edition) without being declared that way using codice_13.