rollslab

Could one not conceivably take a medium, such as stone or wood, or perhaps even a naturally occuring tree trunk, and shape, carve, chip or slice the material into a foreshortened ball, or disk which, by its very nature, rotating around its central point of transformation in one plan (its axis of rotation, one might say), would move forward with much greater ease due to its natural shape, circular, that permits it to roll, especially downhill.

Might one not, further, somehow support a load, perhaps by driving a shaft or pole through this central axis and carefully balancing at either extreme of this pole one half of the total load, be it soil or grain or eggs or what have you, hung with chords from a bag, one at each end, which are tied loosely enough to permit the pole to slip around with ease, never snagging nor tangling the coils of rope.

Thus a farmer could carry a heavier load using this 'rollslab' and with much less effort, and he need only take great care to ensure the loads are balanced evenly and do not slip and produce disasterous consequences.