You are certain these floor tiles were straight at some point. They were carefully formed out of raw material, either with a simple chisel or with the help of a more complex device. But they are not straight any more. Nature always seems to find a way to make things less straight as they age - what starts as a perfectly cut stone, eventually becomes more round. There are many ways this could happen, and ways it could have been delayed if someone actually lived here. But whether or not it's cared for, this could not have been completly prevented. That would be against the laws of thermodynamics. Organized structures tend to become more disorganized, to fall apart. As creatures with some control over some surroundings, we can affect objects, we can help entropy either increase or decrease. But these contributions are temporary - in the end, it will always increase. In that sense, it doesn't matter if you cut a stone into a nice sculpture or break it down into rubble - in the long run, it will end up as rubble either way. At least, that is what a nihilist would tell you. But there's a different way to look at it, which may be more appealing. A temporary effect is, of course, still an effect. And the temporary may matter much more than the long-term end state, one which we will never experience ourselves. Why did these people build the building you're standing in? Did they not know it would eventually fall apart? Of course they did. But they were hoping to get a lot of use from it before that happens. It could have served more than a few generations, and with some additional effort of upkeep, survived pretty much as long as it is needed. And that's the real value.