Explain how longshore drift can transport sediment along a shoreline

Longshore drift is the movement of sediment along a shoreline due to a prevailing wind. The swash of waves runs up the beach and transports sediment at the angle of the wind. The backwash transports sediment at a right angle to the shoreline back out towards the sea due to gravity. This causes a 'zig-zag' motion which over time can move entire beaches along the coastline