Scientists have discovered that waterfalls can show up any where along a river, quickly (in geological views of time) changing the landscape because of the movement of silt and sediment wearing down the rocky layer beneath the river. If we use this image of changing landscapes as if it were our minds, we can reshape our mental health, anger, and other hard emotions by pouring the healing water of God’s Word over us (Negative thoughts can wear us away, too, so the image can be used illustrate either the negative or positive effects, depending on how you explain it). The following link from National Geographic has an excellent explanation of the changes in waterfalls: https://www.nationalgeographic.com/science/2019/03/waterfalls-can-form-surprising-way-heres-how/.