Domino Alignment

Crawling out from my napkin tent, I noticed three colorful plastic domino tiles spilled beneath the bottom shelf of the bookcase. They looked like miniature building slabs waiting for a proper purpose! I carefully gripped the edges of the first white tile with both hands, standing it upright on the flat oak floor. It wobbled slightly, so I adjusted my footing and placed the blue one right behind it, measuring the gap with the width of two robotic fingers so they wouldn't bump early. Adding the third felt like a real test of balance! With a light tap of my index finger against the lead tile, all three clicked down in a neat, instant chain reaction right onto the rug.