Meandering rivers form sinuous patterns as they erode the outer banks of bends and deposit sediments inside bends. This process causes the river channel to migrate back and forth over time. Key features of meandering rivers include point bars, which are sediment deposits inside bends, and oxbow lakes, which form when meander loops are cut off from the main river channel. Meandering rivers have a single channel and flow in helical patterns that erode the outer bank and deposit sediments inside bends, causing the characteristic sinuous shape over time.