1 to fill or enter a place in large numbers or amounts -- ~があふれる, ~であふれさせる
2 a large amount of water that covers an area that is usually dry -- 洪水
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
道路がどれだけ長くても、一歩一歩完了することができますし、足跡をマークしなければ、道路がどんなに短くても完了することはできません。