The tile software is now working on a Sinclair Calculator. 

Since there are no current limiting resistors on the board, the software is being developed on a calculator. Once it is debugged and the displays arrive, it will be uploaded to a production board.

https://gitlab.com/arduinoenigma/seven-segment-art-installation/tree/master/Board100x9x13

https://www.pcbway.com/project/shareproject/A_Seven_Segment_Art_Installation__tile_board_.html