You wouldn't like random, but you can achieve it by using a random number generator. They have them on the web. Or you could roll a die. You might also try using the Fibonacci series as a way of spacing the tiles. That describes a great many structures in nature. To the human eye it looks random but pleasing, even though it's not random at all. Your Post-It method should work. Just make sure when you put them up that they're spaced correctly, not so much for the grout lines, as to have the right number of them up and down. Make sure you measure your tiles because nominal 4"x4" are often not that exact size. Instead of the papers, you could use a chalk line (string filled with chalk) to quickly draw where the grout lines will be (remember to include coves, bull noses, etc.), and then just use your 1x1's. If you have a better imagination for positioning than color, you could arrange the actual tiles on the floor as they'd be on the wall. If there's some color variation in the tiles, that's worthwhile anyway. What I do, is start with the view of the whole and put in the first 3-4 to break it up into sections, then start filling in. Sometimes move one this way or that to keep the harmony going. It's much more wholistic than using a numerical rule, but more fun. :)

May_flowers and Feisty68 I do appreciate your input-be blunt! I need it! I am at design dilemma for sure! So, after the thread I started about the gap areas under hood, I debated two ideas- 1. filling space with stainless or 2. ditching upper stainless and using tile... My only reservation with the stainless is that the riser shelf is not as wide the space. It won't look seamless on the sides. Unless I ditch riser shelf, get custom piece and have a shelf built in. With tile-this was my inspiration: https://www.houzz.com/photos/kitchen-renovation-alexandria-va-traditional-kitchen-dc-metro-phvw-vp~386548-traditional-kitchen-dc-metro Granted it has a 2 inch b/s not a 6 inch. Originally I wanted no tile, hence the 6 inch b/s but it looks unfinished with those gaps... If I do a bigger stainless, do you think seeing that the riser shelf is a separate piece is a big deal, or should I try to make it totally seamless by just starting over with a new big sheet, ditching riser, and having custom shelf?

Not really, Trace. One seedling was under the LED panel (which is only 45 watts), one was under the T5HOs and the mature grafted plant is still under the T5HO shelf. I've had to bring the seedlings upstairs because I do not water much in the basement and these will need regular watering as well as some feeding for the buds to fully develop. The grafted one also needs to be brought up, which I will do later. I had positioned it at the back because I was expecting it to slow down and go semi-dormant as it gets colder. I certainly was not expecting it to start blooming. Also, it isn't that cold there yet---my thermometer is still reporting something like 20 to 25C. I've had to snatch my winter-growing xerophytes and kick them back outdoors. Pagan

I'm going to answer my own question as I figured out a solve using Excel, which I have some experience with. I can do this using Microsoft Excel to generate random-image html and then dump that html to view in browser. A little kludgey but works pretty well. Can even vary the image border width / color to get a feel for grout lines / color interplay. The running bond I achieve by having half-width images and then in Excel I programmatically do the right thing for first / last tile on alternating rows.