come, plough, three-branch tree radical (no. 127)
耒 centers on a farming tool used for tilling soil: a plough. The radical sense is the same plough shape used as a component in other characters, and the 'come' meaning is a rare, unrelated usage.
耒 is a pictograph of a plough, with the top horizontal stroke representing the handle and the lower branching strokes the blade or tines. The modern form retains this basic shape.
The top horizontal line is the handle, and the lower three-branch shape is the blade cutting into the earth. Picture a simple wooden plough: 耒.
For ライ, imagine a farmer ploughing a field while singing a cheerful 'lie-lie-lie' tune: lie -> ライ, and the plough turns the soil.