You're staring at a bathroom floor, or maybe a kitchen backsplash, and every tile sits snug against its neighbor — not a sliver of daylight between them. How do they do that? Did someone measure each one down to the millimeter? Did a robot cut them? Or is there a secret?

Here's the trick: tiles fit together without gaps because they're made in molds, and molds are copy machines. One factory makes ten thousand tiles from the same metal frame, so every tile comes out the same size — like cookies from the same cutter. When shapes are identical, they lock together like puzzle pieces.

But wait — no factory is perfect. Tiles aren't robots; they shrink a tiny bit when they dry, or the kiln runs hot one afternoon, and suddenly tile #4,382 is a hair narrower than tile #4,381. So why don't you see gaps?

Because of grout. Grout is the squishy paste installers smoosh into the cracks after the tiles go down. It's flexible when wet, so it fills whatever space is there — wide crack, narrow crack, doesn't matter. Once it dries, it locks everything in place and hides the size wobbles.

Think of grout as the forgiveness layer. The tiles just have to be close — within a millimeter or two. The grout does the final fit, like caulking a window or icing between cake layers. It's why grout lines are usually a different color: they're not tile, they're the glue-and-filler that makes the tile look perfect.

Now, some tiles tesselate — a fancy word meaning they lock together by shape, not just size. Hexagons, for instance, fit six-around-one with no wasted space, like a honeycomb. Squares do it too: four corners meet at a point, every time. The geometry itself refuses to leave gaps.

Installers also use spacers — little plastic crosses or T-shapes they stick between tiles while the adhesive is wet. Spacers keep the gaps even, so the grout lines look intentional, not random. Later they pull the spacers out and fill the grooves. It's like putting training wheels on geometry.

So the truth is: tiles don't fit together without gaps. They fit together with tiny, planned, grout-filled gaps that make the whole floor look seamless. The art isn't in cutting every tile perfectly — it's in knowing that "perfect" is really "close enough, plus paste."