bkay

I don't think there is a "hard and fast" rule. This is a traditional block that was passed down through the ages. Our ancestors made this quilt block with what they had. The overwhelming majority of quilts were made to keep you warm in the winter. Very few were made for "show" or display as few women had spare time for aesthetics.

However, the first two logs should have the same value (light or dark), as that is the start of that "side" of the block. Then the next two logs would be the other value. This is if you are doing a traditional block with a dark side and a light side, for lack of a better description. I just googled "log cabin quilt" to get multiple photos at once.

I would suggest that you make it like you like. If you like the first two sides to be the same, make it that way. If I was still questioning my choice, I would go to pinterest or google and see how others have done it.

bkay