Stryped1:

I have no idea what the indentations on the bottom of commercial hardwood flooring is, but I think you need to be aware that most woods have tannins in them. When you use steel nails to install the hardwood flooring, and that floor subsequently gets wet, you will have iron ions from the rusting nails coming into contact with the tannins in the wood and producing a chemical called "iron gall ink". This is a black substance that forms right inside the wood.

Look at any picture of any old wooden flooring, and you will see black stains around every nail used to hold the wood flooring down. This is the result of people mopping that hardwood flooring and the resulting rust reacting with the tannins in the wood to form that black ink which penetrates into the wood and stains it.

Similarily, if you ever see a black round ring on a hardwood floor, that's caused by overwatering a floorstanding plant. The water that seeps out of the bottom of the pot is rich in iron ions from passing through the soil, and that iron rich water than forms a round puddle on the floor. The tannins in the wood react with the iron in the water to form a black round stain inside the wood.

So, make your own hardwood flooring, but keep in mind that your hardwood will stain if you don't protect it from iron nails, iron in the soil of potted plants, and other sources of iron. Google "Iron Gall Ink" if you want to find out more about it.