I'd say it must be a fun mental exercise. While constraints in a language aren't 'fun' for me, choreography of the CPU (i.e the way the program is architected,

I'd say it must be a fun mental exercise. While constraints in a language aren't 'fun' for me, choreography of the CPU (i.e the way the program is architected, written and executed), is. Compare it to art where an artist only uses a pencil, or limited colour pallet, or limited materials. Or even art from just a single, constant weighted line: http://www.ignant.de/2013/08/12/one-line-drawing/ http://www.ignant.de/2013/08/12/one-line-drawing/ There are other benefits to this program in general, one in the area of security and exploring the options for different attack vectors.