User blog comment:DrCeasium/Hyperfactorial multidimensional arrays/@comment-5529393-20130509054910/@comment-7484840-20130509170438

I use the @ symbol to show part of an array that can contain anything, from nothing to a whole dimensional sub-array. When there is no subscript, anything at all can go there. When there is a subscript, there is another rule governing what the @ can represent, for example, only 1's and seperators, or no dimensional seperators at all (other than (0)'s, or commas). They do not always have commas after them because the last thing in them could be a higher seperator. (just in case anybody is wondering)