Years ago I saw a program with Bob Vila putting down a floor using the end grain of the wood. They spaced the wood like a tile floor. The grout that filled the space was a mixture of sawdust and
Polyurethane. I would like a floor like this in my home. I could use more info on how to mix the grout. Any help would be appreciated.

That was the Cobblewood flooring installation from the Chicago Grey stone.

Use 3/8 or 1/2 inch thickness of wood. Type of wood is user preference but it should be as dry as possible. The wood tiles can be just about any size or shape as long as they are not too large or warping will occur.
The grout for the cobblewood flooring is composed of sawdust from the wood mixed with a fast-drying oil-based sealer in a ratio of 2 parts sawdust to 1 part sealer add any stain to grout to your liking.

Insure you have a standard sub-floor.
First glue floor down, use regular tile mastic as an adhesive. rubber based instead of Water based is best.
Let set for two days...
Then grout, Pour the grout on the floor push it into the cracks using a rubber trowel or your hands. Trowel in the grout. Squeegee off the excess. Steel wool the face of the wood tiles to remove any remaining excess grout that could dry to the top of the bricks.
Let it sit over night and then apply another coat of oil-based sealer the next day.

Let set for one day.
Then do final coat of varnish, stain etc.

Maintain like any wood floor. Oil it every 2 years using wood floor oil. Varnish once a year. Buff once a month.