flemish strings are built 'in the air' by twisting bundles of string fiber together and braiding the unserved string loops.
advantage is that no real jigs are needed, disadvantage is that it can be difficult to accurately create, and repeat, a specific string length.
endless strings are built on a jig, by spinning a continuous fiber strand around two posts, the string loops are served close.
advantage is that is easy to create, and recreate, specific length bowstrings, disadvantage is that a big string jig is required.