Tatsuo Horiuchi: The 73-year old Excel spreadsheet artist (2013)
It looks like he's drawing on top of the spreadsheet, rather than using the cells.I've experimented with using a combination of conditional formatting and "creative" formula writing to produce algorithmically generated patterns/designs with some success...Basically set cell height and width to 1 and you have a pixel grid. Use formulas to drive values which drives conditional formatting.